We had a not-as-aged-as-yours puppy have a medical issue. My heart goes out to to you and your family (including your pup).
Although the situations are always different, I can offer my opinion: QUALITY of life. Please take this into account when thinking about what you will do for him (or her). Although it is tough, you will go on, however for your dog, think of what is best for them.
In our case we opted to NOT do extensive (and painful) life extending procedures done. Rather, we did everything we could to make our family member (the dog) as comfortable as long as possible.
In our case the procedure would have only added a projected 6-months. As it turned out, we got that much time making the little guy comfortable. I have to believe that we did the right thing in our case. It all still brings a tear to my eye
to think about Max and to think about how good he was.
All the best to you and your puppy.