My dad had the lap band surgery with GREAT results. It was crazy to watch him shrink so quickly. He had the surgery in the morning and was home walking around the same afternoon and they only made something like 4 small incisions on his stomach. I've seen comments from some people saying they didn't really notice anything quickly but I guess that's because results vary from person to person. When my father had the surgery it was definitely life changing. He went all out though, which was fantastic. He ate mostly veggies and water, nothing heavy, and he exercised a lot. Like gastric bypass, you have to eat crazy small portions and if you don't you'll get sick and there's still the possibility that overtime it can be reversed. Meaning, if you continue to overeat your stomach will simply stretch the bands they put on. I know you can go in to get them tightened, loosened and/or removed alltogether.
Has your friend talked to a doctor yet? He may not be a good candidate for one or the other which would make the decision for him/her. Also, my dad's insurance covered his lap band procedure so your friend should definitely talk to his/her doctor to see if they can help with that. They required referrals, a doctor's recommendation letter and he had to have some tests (sleep apnea for one) for my dad to have it covered.
Good luck.