Chicory - I have a family member that sounds very similar to your son. Everyone enabled him with a rent free place, new cars, money, etc. Then one day, his dad had enough! It didn't end pretty but it ended.
He went out on his own that day, got and kept a job and eventually married. He is still some what estranged from the family but he is happy, living the life he wants. Just wanted to share my ES&H.
Ps. He refused all help but once he went out on his own, he actually did much better then anyone expected.