Again, I don't know much about Tricare, but to my mind, having a lap band REMOVED is not a bariatric procedure. It could be presented as treatment of a complication of a bariatric surgery that never worked right, in the context of increasing evidence of the high rate of lap band failing and requiring removal, with or without revision (there is another thread in the "news" forum where I linked to an article on this very subject).
Regarding situational depression, I'm glad you're getting treatment for this, because even when someone has excellent reason to be depressed, treatment still helps.
and regarding your grandma, and the family's general attitude of judgement and lack of understanding, sometimes you just have to forge ahead despite this, gather up your courage, and ask. If the price you pay is judgement, but you get the money, it's more than worth it. Remember this isn't cosmetic surgery, it's medically necessary care. Family is important, but even with family I learned a long time ago not to let their opinions and/or judgement get in my way.