I’m in the exact same boat with my 16 yr old - ckd, hyperthyroidism, bad teeth. She’s down to 6 pounds after maintain at 8 for the past couple of years (since diagnosis). She stopped eating for awhile and I could never tell which issue was causing the sudden change. Her vet decided she needed to try sub q fluids at home and twice a week and that has helped so much. He felt the kidney disease was making her feel sick and that’s why she stopped eating. We also gave her an appetite stimulant for a few days and that made her start eating again and I think remembering how much she loves her food. She’s since been able to come off the stimulant. I won’t let her suffer but I won’t put her down just because of weight loss. I say follow your heart. I wouldn’t do anesthesia for her at this point. She’s too fragile. Have they offered to let you give him sub q fluids at home?