That's awful about your poor wife and grandson! But you can't get any better place for care for both of them than the Mayo Clinic! I live in Washington State so it's impossible for me or family members to go there but we do use their website for medical information. It's been very helpful.
That's too bad about your wife losing weight! Has she tried eating ice cream, pudding or custard? Those would possibly be soothing and easy on her stomach.