Thanks for your comments. Congratulations to your friend, Diane, for persevering with her weight loss. It's a tough journey.
These days more and more insurance companies are covering bariatric surgery. That's because they know that when someone's weight is in the normal range, health risks like diabetes are reduced or disappear altogether. This makes forking out the money for surgery a good investment for insurance companies.
Unfortunately, insurers still consider post weight loss plastic surgery a cosmetic issue. "Not medically necessary," is exactly how they look at it.
From many conversations with plastic surgeons, I've found that sometimes an insurance company can be persuaded to cover some of the cost of eliminating the excess skin. Seems like women are most often successful when they need breast surgery for further reduction and/or lift. And occasionally an insurance company will cover another procedure, like abdominoplasty, if they can be convinced that paying for surgery will be cheaper than paying to treat rashes, infections and so on over the long haul.
As your friend probably knows, the key to making a good case is documentation. Letters from doctors, photos of rashes, copies of prescriptions for anti-inflammatory creams, etc. And appealing when turned down.
Even then, most people do not win against insurance companies. Enough said about that, especially these days.