You are going to have to start small. This situation didn't develop overnight and unless you kick him out and cut him off, then changing his behavior will be a long and difficult process. You and your wife need to be in complete agreement and stand firm together. No undercutting the other or this won't work.
Your son needs to be taught discipline and responsibility. Those come with severe consequences for non-compliance. Everyone given a choice would like to behave as he does. You need to remove that choice.
Fist would be work schedule regardless if he has a job. Up, showered, dressed at the same reasonable time everyday. Chores assigned and completed every day. His new job is finding a new job. 9-5 every weekday he needs to do nothing but look for a job. If the job he finds is part time, then time not spent working is spent looking for a second or a better job.
Once employed, he needs to contribute rent and assume his own bills for phone, car, insurance, and so forth.
This won't be easy and he will push back as hard as he can. No one wants to give up games and friends, free room and board for work and responsibilities. Start weaning him off his reliance and dependance on you and your wife. Teach him to be accountable for his own actions. Show him that life has consequences and rewards.
best of luck!