Read other letters about this article
with Zaynab's and pookastew's advice is that it's even less likely that the LW's father will pack up and go with his son. In fact, I'll bet the LW has entertained these thoughts, maybe even voiced them aloud, but he may already know that his father is so enmeshed in this situation that he could never leave, at least not voluntarily.
But going to a meeting of other people who have something in common with him, people outside his family who might give him the friendship and respect and decency he won't get at home--that's a baby step. And maybe one that will help him on the way to moving out.
I speak as someone who has an older parent who's not nearly this dysfunctional, but whom I know--no matter how much help I might offer, no matter how prepared I am to take her on--she will never take me up on it.