My Jack is 9 years old. he has osteo of the back left femur. I know exactly how you are feeling right now. He was diagnosed May 22. I know. I have just gone through exactly what you arre going through. In the end, I decided on palliative care for my boy. No amputation. Jack is so shy and scared that I felt the amp and chemo was not right for him. That doesn't mean it is not right for another dog or another family.
He currently is on Tramadol and Meloxocam for pain. Aside for the occasional shakiness of that leg, at this moment he is happy, painfree and living his life joyously. We go for walks. he trots around his backyard and lies in the sun. He gets whatever wonderful treat I can find for him. He loves to eat still.
I look at him and can't believe are time together is coming to an end but he doesn't think that way so I am determined to enjoy the days or weeks or months that we have. I promised him he wouldn't suffer, that he could leave me in his own bed in his own home when he is ready. But right now? We are happy.
My heart grieves for yours,