Gastric Bypass Cost

A close friend of mine is considered morbidly obese, with a BMI of 50+.
He has tried to lose weight on his own for years now, and has, on several occasions, lost a little. He has, unfortunately, damaged both of his knees in the past which makes typical exercise (which most of us take for granted) something that is almost impossible. He’s able to do normal things (and quite well, I might add, for his weight), but if he over-stresses either (or both) of his knees, he is likely to further damage his MCLs.
His eating habits are not the best, but his caloric intake is not overwhelming (and is typical of a person of his age). I think that his lack of activity has essentially destroyed his metabolism, honestly.
He has considered gastric bypass as well as other alternatives, but the cost is more than he can afford. Payment plans are not an option at this point. He’d rather stay away from surgery, anyway.
This is a very serious matter, and I’m not looking for “tell him to drop the candy bar and go for a walk”-type answers. I want to help him (and he wants help), and I’m really worried about his health.