wow.
This guy posted in feb.
Im not sure he will be back.
but my suggestion, watching my mother go through this right now with my 20 year old brother is to maybe seek some help.
Depression is caused by drinking and using drugs.
but, beyond that, it may be a real chemical imbalance that is stopping him from being and feeling like a normal person.
Some sort of medication may help him.
getting him into see a therapist may benefit him as well, if he is feeling like he can not talk to you or your wife.
He may need a little time to dump some emotional baggage, and find a good wake up call.. what ever that may be.
If it were me, I would be working on some tough love rules.
Not limited to , but begining with financial responsibility for living in your home. Young people eat ALOT.

He could start with having / needing to provide food.
Pay a little of the bills
but .. you are still faced with how to get him into a job when he wont get up and put in an application. That step may be easier with a therapist?