My son

My son was approved for RNY.  He will be 19 in May.  I am all for him getting healthy but I am scared that he is not responsible enough to remember his vitamins and do everything he needs to do after having his surgery.  He does work part time and take 4 classes at the community college, but he seems immature and unorganized.  (Holy crap his bedroom scares me at times!)  Through talking to parents of other guys his age, they all seem to be in that lazy-irresponsible phase right now. 
I guess my question is:  Is there anyone else that has gone through this with their son?  or Is there an 18-19 year old guy out there that can relate?  Any advice?

This is scaring me.  We go to his pre-surgery class on 2/11/09.  He is old enough to make his own choices, but I am mom so I want him to succeed and be healthy.
Thanks in advance.
Joann