That's unfortunate. Sounds like you were really young when you had him and he's struggling now. I hope he figures life out. good luck with everything.
Tough love....my parents did it that way with me and my brother and we learned to figure it out ourselves and appreciate life more. If he's that bad, let him figure it out. It will sick to see him struggle but it will be worth it in the long run. He will learn important life lessons and eat it takes to be a successful, thriving adult.
No but don't put yourself through the stress. He's 21 you have completed your obligation to support him any longer. Pray for him that he will change his ways but not on your time. You have other kids to consider also.