Has your friend ANY idea of how seriously fucked up this woman has to be for SS to tell him that if she has contact with her son, they will remove him.
Does he realise how serious that is?
2 women a week are killed by their partners, 2 men a month are killed by theirs.
It is as grim as it gets for him now, and I deeply sympathise, having been a DV victim myself.
Please tell him that it will get better, and really soon, that he will grow, heal, learn and get back to the wonderful, strong, warm funny person he was before her.
This time next year, if he puts time and effort into himself, his life will have transformed completely for thew better. Much sooner than this he will wonder what on earth he was doing with her.
He needsa to know that none of this was his fault, that he didn't cause any of this and that she will do it again, and again and again. She won't change ever, she will only get worse. She will end up in prison, possibly for murder, but not his, and not his DC, as long as he keeps himself and his son away from this abusive monster.
Tell him he's welcome here anytime, that we're all here to help him, but that Mankind and other support groups will be vital to him in addition to this.
He has nothing to be ashamed of, he didn't do anything wrong, he's saving his child, that's about as heroic as it can possibly be.
Tell him good luck from us, and never forget that he can lean on us, if it's helpful.