OP, I had a similar father, without the added family court trauma. Cutting contact is a step but that alone will not free DS from the experience or process the feelings of grief, etc. from this being his dad's idea of "family behavior."
Some things that were life changing for me, resources for him now or later. It will impact him and his future formed family without some unpacking of the experience (what he had and also what he did not have). It also has carry over effects re: work, sense of self, etc. that the "cut off" does not in and of itself repair. Sometimes patterns like drinking can be repeated or unconsciously become workaholism or other unhealthy behaviors without working through the underlying feelings. Anger can be healthy but it typically covers a lot of vulnerable feelings. DS must have felt quite powerless with the threatened litigation at 14, coerced, aware of money as a weapon and wanting to protect himself and you without a way to do so, etc.
https://adultchildren.org/
Daily meditation (can sign up for free daily email) today's may resonate
https://adultchildren.org/meditation/
March 02
Trait Three
"We are frightened by angry people and any personal criticism." BRB p. 11
It's insidious - the abuse we experienced. For many of us, our caregivers didn't just get mad, they got angry and enraged. And it could be over something simple. Maybe we were out doing normal kid stuff, but because we had an angry parent waiting at home, we were never sure what to expect. We were repeatedly blindsided with accusations that said we were no good, selfish, irresponsible, uppity, or a whole host of other shaming language. Or maybe it happened to a sibling, which was just as bad because we knew it could be turned on us at any time.
Is it any wonder that as adults we almost visibly flinched when we were faced with angry people? We carried the fear of being criticized with us like a banner that said, "I'm an easy target. I won't even argue with you because I don't have a voice."
But as we start to find our voice in ACA, we begin to separate the anger from the words, and the words from reality. We do not deserve to be talked to ‘like that.' And we didn't deserve it as a child. We were innocent! And now, as we learn to reparent ourselves, we can tell our Inner Child that we will protect them when someone is angry or critical. We can do for ourselves what others should have done for us.
On this day I will remember that another person's anger is not mine. If I hear criticism, I can separate truth from fiction.
Also a fantastic resource for those who grew up in a chaotic family:
https://www.amazon.com/Loving-Parent-Guidebook-Softcover-Spiralbound/
Happy birthday to your DS. I hope this begins a happy, healthy and less stressed time for both of you.