The RAF went through a similar rediculous process a few years ago. Indeed, a friend of mine, who is obviously of a heavy build, was told to lose a rediculous amount of weight. He went to see a private expert with the figures the RAF gave him. He was advised by his consultant that if he lost that amount of weight it could endanger his life through heart problems, liver failure etc. He was further advised that any doctor telling him to do so would be in breach of several professional guidelines. The independant consultant gave him a letter stating as much which he took to the medical board.
He never lost a pound, the medics all panicked as someone had found them out, and he now flys everyday. He's still of a heavy build but a lot thinner than most of the Navs!!!
Perhaps your friend could/should seek a second opinion from a real expert.
Cheers, good luck and don't be too upset when Martin Johnson lifts the old William Webb Ellis!!
R&R