Ya, the problem is that he is 19 and medically speaking, his parents can no longer have control over his meds or psyc treatments.
He needs to deal with his ADD and it sounds like he has given up. I don't know if this will help, but it is a link to an adult ADD site by an adult with ADD. It has a lot of very helpful information. He (or you) might find it helpful.
The site is - http://jeffsaddmind.com/for-first-time-visitors
And yes, I agree with the above. It probably is time for some helpful, intelligent "tough love".
Well, I think asking him to say "thank you" should be so far down on the list of priorities it's not even on the page. Saying "thank you so much" takes 2 seconds and doesn't solve any of his problems -
Video games will be the scourge of this generation. They are addictive, literally, in that they reset the brain endorphin release system. I think you could probably see a difference in an addicted gamer's brain vs. the brain of an engaged, active adult on MRI, truthfully.
So where is he getting his internet connection?
Hi there. Well, you've rescued a kid that was being taught a lesson in responsibility. Probably not a great plan. I know it hurts to think of a loved one who may not have a roof over their head but as you can see what his parents saw now . . . he really does need tough love.
I would allow his parents to make the decision about help and hopefully he will rise to the occasion and see that he has to grow up. good luck