I'm so sorry, and this on top of the rift with your parents must be overwhelming.
First - he's a drug addict. He's addicted to the physical sensations of drink, and the social and ritual aspects of it, too.
The 'life and soul of the party' in his 20s becomes a distasteful figure as he ages and drink takes him over.
For addicts, their primary relationship is with their drug. They love it more than they love their family.
As they get older they may seek more and more and more to get the buzz, the high, the oblivion. Whether opium, coke, heroin, crack, alcohol, whatever - it's the same.
It is often described as an illness - it's also a choice. And getting help, committing, listening, following through, or not, are also choices.
The implications are huge.
Pissing away family money
Ruining personal and professional reputation (I wonder if his condition was noticed at work?)
Soiling your home, probably leaving you to do the disgusting cleanup
Your children have NOTICED and they understand what he's choosing to do and how he's treating you
Decades of subjecting his system to what is essentially a poison will place him at risk of cancers, liver desease, brain damage - you name it, and you'll be the one stuck caring for him
A drunk angry man is very possibly a danger to your children and yourself
He's potentially a danger to himself and others - falling, crashing his car, getting stuck passed out outside in the middle of winter, falling downstairs - all are possible.
Are you genuinely intending to keep subjecting your children to this? You also do have a choice.
He's now committing DARVO - deny, attack, reversing victim and offender - and gaslighting and insulting you. Remember his lashing out is nonsense - this is not who you are.
We don't know the circumstances of your rift with your family. Is it a permanent done thing, or could there be conversation, understanding, help from them? Do they know the full extent of what's happening? Do you have siblings, friends who could help?
Please take in what women here are telling you about how it felt growing up with an alcoholic and abusive parent