OMG, I'm reading the post and going, "AL-ANON says he needs a GOAL???"
No, fer ****'s sake (I put in the asterisks myself), Al-Anon doesn't have anything to say about what the alcoholic "needs". Sounds like his Dad needs to learn that he doesn't have any more power over you than he does over his son.
Sounds to me like the Dad is being manipulated by the son's threats, and the Dad in turn is trying to manipulate you. Look at it this way. The Dad is scared, probably, by the suicide threats. He probably thinks it would "help" for him to have his family back. Not his business, and he can't possibly know what is best for anyone else.
If I were you I'd be as compassionate as possible toward the Dad, but let him know that you will handle your own recovery.