i'm sorry to hear, but i'm afraid you have some tough times ahead of you.

i had to go through the same exact thing 5 years ago with my german sheppard of 14 years. she was my baby, my little girl, i weened her with a bottle from a baby when her mother refuse to feed her any longer. she even knew judo and tripped other dogs/people using judo techniques that i taught her (grab one leg and use her body to get push/pull the other leg until they fell).

it started with her getting diabetes. we had her on insulin shots plus a strict diet. but the diabetes was never under control and it created cataracts in her right eye. later she was diagnosed with osteo-sarcoma in the left rear leg and it came on very fast. at first everyone including 2 vets thought it was just arthritis setting in on an older dog causing her to limp slightly. then the leg grew hard and stiff and it started to gain in mass. i would carry her up and down the stairs, outside, on and off the couch whenever she wanted to move.

we were also advised to remove the leg and undergo chemo. we were given alot of pain meds. we were told it only subsided the pain, not mask it or remove it... she would still feel the pain constantly. however i couldn't bare the thought of her having to learn to walk and move on 3 legs at her age. after 2-3 months of trying to convince myself that she still had more time left, i finally gave in seeing how uncomfortable and tired she was. we put her to sleep and i cried for weeks. typing this still brings a tear to my eye.

it was the most difficult decision of my life. i still mourn her passing to this day... good news is that i have TONS of great memories with her that i will never forget.

cherish the time you have with your dog. he'll love spending that time with you.