I feel for your friend, it's hard to have 2 old dogs going at the same time. As others have said, the biopsy is really going to be the key. Sadly most oral tumors are malignant. They rarely can be removed completely, and grow back. My brother went through this with one of his dogs, the tumor was debulked twice, and when it grew back again he decided not to put her through any more. It continued to grow to the point she had trouble eating, and he had her put down. I'm sure it was a shock for your friend to hear the prognosis of 6 mos., and some may think that the vet was cruel or insensitive, however, some people have a hard time recognizing that their animals are in pain or will die. Your friend is against euthanasia, and I'm sure her vet could see what she was putting the other dog through. I think he felt that she needed to be able to prepare herself, and IMO, that is kinder in the long run. Giving false hope is not kind. I'm not saying you shouldn't wait for the biopsy, there is a possibility that it is benign, and you are a good friend for supporting her. But if the tumor comes back as malignant, the kind thing is to gently help her get her head around the idea that he will die. I don't see anything wrong with her spoiling the dog meanwhile. It is not likely to hurt him, as long as she doesn't cause a badly upset stomach, and it will make her feel better.