He might consider the 17-day Diet. You can get the book from the library or used book store, and lose a very substantial amount. I lost 12 lbs., I think, and I was a smallish girl, not a great big man, to start with.
My friend Dave is a big guy, not really overweight but well over 6 feet ... but Anoreth is tiny.
Busdaddy and I are pretty much the same height. He has a tendency to gain weight, anyway, and had to work hard when he was in the army to keep his BMI within acceptable limits.
I can stand to lose 40+ pounds, but he has to lose more than double that amount.