My 15 year old "pup" died last year due to a stomach tumor. I was given the option of surgery and chemo and the vets were willing to do it to buy another year or two. When I asked what they would do if they were me they told me they wouldn't do it; it could have been hell for him to go through. I put him down the same day and cried so hard one of the vets had to drive me home. I wish you the best. Cherish the memories.