This is great progress. It's up to him now - does he go get help or use the abuse as an excuse to just keep doing what he's doing? Hmmm, that is the question. As for being afraid of being scared and alone if he sees a counsellor, this makes no sense; he WILL be alone and scared if he DOESN'T get help because you're not going to stick around if he doesn't get help! His fear is not rational, he cannot be hurt by what has already hurt him and he can take the power of those memories away by sharing them with someone who can help him put them in their place.
That's for him to find out. Not you. You don't wear this, you have your own baggage and it's not fair to ask you to carry someone else's baggage as well as your own.
I hope someone sees your email to join the Family Crisis forum soon