Dynamite and Doormats

I really enjoyed reading this, and you've definitely improved your discipline, NP.  I've known people like that in my life ( thankfully it wasn't my father ).  It's very sad what their behaviour solidified as; without reception there is no growth.  Their mind becomes stagnant in habit.  Hopefully one day it will change for the better, and he can actually get to know his family on their own terms of existence.

Because you have requested honest critique I would honor it with the following:

You never stop ranting:
talking, yelling, screaming, and debating.

Here I would use a colon, which indicates an ensuing list ( which would also connect the independent phrase with the fragment ).  I would also suggest ( throughout the verse ) that you cap only the beginning of sentences because you are using standard punctuation throughout.

Pauses not ment ( meant ) for my words( ; )
but( , )for your mouth to catch up.

Here I've connected two independent clauses with a semicolon, and revised the second to a lowercase.  This keeps the clauses independent while connecting them closely in thought.  The comma ensuing 'but' allows the reader to briefly pause before the punch of the line hits them.  

New leaves are new information,
And you're ( your ) roots are impeccable
At feeding ( nourishing ) your tree.

Here I am going to suggest you replace the second 'new' with 'fresh', so the consonance of the 's' sound resonate with information.  I am also going to suggest that you replace feeding with nourishing so the entire stanza becomes lyrical when read.  You'll have the assonance of 'o' playing into tion/your/roots, and again that delicious consonance of 's' in L1 would carry on.  I've also connected with a semicolon and changed caps of L1 & 2  to lowercase.  Read the below alterations aloud against the original and see what you think:

New leaves are fresh information;
and, your roots are impeccable
at nourishing your tree.

Your voice is like dynamite in the cliffside( : )
booming, deafening, destroying ( — )
all other words in it's ( its ) way( ; )
you never stop lighting and throwing
new ideas into the mountains.

Here again I've repeated the colon to precede the list, and then used an em dash to separate and yet connect L2 & 3, while lowercasing them.  Then I've used a semicolon to connect L3 with L4/5.  I love that you have emphasized by italicizing.  I can't italicize in a response, but highly recommend you keep it as such!  What all this does is improve the flow of the stanza without abrupt stops or caps in the middle of sentences despite them starting new lines.

Your voice is like dynamite in the cliffside:
booming, deafening, destroying—
all other words in its way;
you never stop lighting and throwing
new ideas into the mountains.

I want you to listen—
I have dynamite too( ; but, ) I don't want to use it
because( , ) I know why you do this. . .
why you're like this.

Again, all I've done is insert punctuation to connect thoughts, which will allow the reader a smoother experience when reading.  In this stanza, I imagined you gently trying to explain to your father that others have thoughts and feelings too.  I couldn't envision you loud or brash at this point.

I want you to listen—
I have dynamite too; but, I don't want to use it
because, I know why you do this. . .
why you're like this.

You have decades of hurt( : )
Inside and out, mentally and physically—
years of wondering alone, in silence
blasting away [the] years of quiet[ ; ]
[You're] fighting [the] mountains.

I like how you've used the hyphen; however, it's incorrect usage. What you want here is an em/en dash; however, what I suggest is a colon preceding the list.  The hyphen is mostly used to combine words into compounds ( long-term, mother-in-law, etc. )  and separate numbers that are not inclusive (phone , social security, etc. ); or, a minus sign in mathematics.  

The em dash is the mark most of us picture when we hear the term dash. It is significantly longer than the hyphen.

The em dash creates strong breaks in sentence structures. They can even be used in pairs like parentheses—that is, to enclose a word, or a phrase, or a clause—or they can be used alone to detach one end of a sentence from the main body, particularly in sentences that are long, complex, or contain a number of commas. If you confuse the em dash with the hyphen, it can render a sentence virtually impossible to read. If we had used a hyphen in place of each dash two sentences ago, it would seem as though we had hyphenated two pairs of words in the sentence: “parentheses-that” and “clause-or,” neither of which makes any sense.  

The rule of thumb I use is reserving em dashes for breaks where commas are not a strong enough break. If a comma (or a pair of them) works, I use it.  Parentheses tend to downplay an idea or suggest information in them is helpful but not necessary. Em dashes draw attention to the information, signaling the reader it is important.

Fun facts about the em/en dash you might not know:

The en dash is slightly longer than the hyphen but not as long as the em dash, and is the width of the letter “N,” whereas the em dash is the width of the letter “M”—thus their names!  The en dash means, quite simply, “through" and used largely to indicate inclusive dates and numbers:  January 1–August 17; pp. 37–59.

So back to your stanza! LOL!  Do you really need the words I've bracketed to make your point?  Read the below and tell me what you think.

You have decades of hurt:
inside and out, mentally and physically—
years of wondering alone, in silence
blasting away years of quiet
fighting mountains.

I'm wondering if there is a substitute we could use for one of the 'years', 'decades, perhaps; or, maybe "a lifetime"?

a lifetime of wondering alone, in silence

Think about it.

So, like many times before
( you ) sweep[ing] my words under rugs ( ; )
( but, ) I hide my dynamite there too.

L1 isn't an independent clause; therefore, should not end with a period. Because this is a new stanza, I would highlight who you are addressing with 'you' in L2, thus altering the tense of sweeping to sweep. Where you hide your dynamite is a surprise!  Therefore, you want to build up to that surprise, i.e. - use a semicolon to connect; however, use a conjunction ( in this case 'but' ) to contrast what has already been mentioned! What a shock I was not expecting!

So, like many times before
you sweep my words under rugs;
but, I hide my dynamite there too.

See the difference in reading?

The final stanza is tricky because you change voices from addressing your father to addressing the reader; therefore, you need some sort of separation between stanzas to denote a change of thought.  You can successfully do this in various ways: period, number, em dash, etc. However, if you do choose a number, then you would need to number the first part of the poem as well.  I'm going to select a period and space:

.

And this poem, he'll never see [ . ] ( — )
[i]t's too far underground.
I don't think he could understand
[w]hat my words mean to me.

This is a very succinct ending almost denoting the acceptance of the way things are. You've penned this verse in a cathartic way for yourself as a release, never intending to send to the recipient. Or that's the essence I'm garnering.  

Thank you for allowing me the opportunity to offer suggestions honestly and openly.  You're a good writer, just remember that critique, with the exception of proper spelling, grammar, and punctuation ( unless intentionally incorrect for purposes of dialect ), is largely opinion.  You will see broken rules in some of the greatest poets who ever lived,  E.E. Cummings, for example; however, I honestly believe that writers such as himself were familiar with the basics of language; therefore, knew how to break rules successfully.  Just as any good painter must learn the fundamentals of paint; thus must we writers learn the fundamentals of language.

Knowing the rules in order to break them successfully is essential.

Thank you again for your help and advice on my work, and tips to help the poem. I really appreciate the honesty you give, it's very gentle. You really understood what I was trying to say, who I was saying it to, and the intonation of the poem.
I've taken some notes, and will be updating the poem some point tomorrow!
Thank you again Ahavati!

It's my pleasure to work with a talented writer such as yourself, NP.  Thank you for accepting it in the spirit it was given. I'm holding a workshop next week in the forum for punctuation.  Perhaps you can join us if interested.

https://deepundergroundpoetry.com/forum/workshop/read/11232/

Well, there's not much else to contribute critique-wise LOL! Ahavati covered everything comprehensively like a snowstorm in Montana.

I do want to say the final stanza came as a complete surprise. Brilliant storytelling execution there.