Was the blood test offered, if not, maybe ask for it? It shows kidney function in aged pets and is a guide as to how the anaesthetic might affect them.
Is it tablets, gel or liquids as pain relief? When mine had chemo therapy, thinly sliced ham was the thing she would eat with a pill wrapped in. I did try sausage but too many made her sick up the tablet which I wasn't supposed to handle
. Cheese did the same. Sometimes I would find the pill under the radiator and wonder which day she had managed to spit it out!