Just thought you should hear from someone who has had an excellent response to Wellbutrin. I've been on it for about 4 years now, and about 6 months ago started the XL. I've had no serious side effects. I think the worse thing is dry mouth - I have to make sure I'm drinking extra water, but that's not always a bad thing.
I can't remember how I felt when I first started, but it's fairly normal if I recall to feel "strange" for 4-5 days. Another thing to consider is his dose might be a bit to high for him.
But anyway, I just wanted to say this has worked wonders for me personally.
Good luck!