I recieved the sonogram results and the vet says my cat has a small kidney and 2 lumps. What should I do?

One of the lumps is on her kidney and the other is near her ovary. Vet says not much can be done for her now. I have been assist-feeding her. She has absolutely no interest in food, except water which she is still drinking on her own. What should I do? I don't see her in no visible pain, she purrs when we get near her and touch her but she just won't eat. I have been assist-feeding her chicken Gerber baby food with water. Some family members tell me I should put her down now. I can't come to terms with it. I have decided if I see her in visible pain, I will definitely have no option. Am I doing the right thing? I want her to get better but I really don't think that will be the case. I have tried everything in making her interested in food and nothing. How should I proceed? This pains and grieves me beyond belief! She is 12 now. Not exactly an old cat....