Good Luck to you and your family as well!My son is currently in a residential facility and I am hoping for some help with aftercare transition also. Sorry I have no advice, but wanted to say I'm in the same shoes trying to find help. He's got 11 months until discharge, but I'm currently working through ideas with my therapist to help my anxiety levels. Good luck to you and your son.
Much will depend on your specific situation - why he needed residential to begin with, the progress he (as well as your family) has made since his placement, and the reasons for his discharge. Some kids are released because insurance runs out even though they aren't really ready.
Do you feel your son is ready to return home? Is everybody in the household ready to have him home?
I would think that at minimum, he needs regular (weekly or more frequently) therapist visits, and an IEP to address his educational needs.
Keep us posted, we will be happy to help you.