Aztec the dog

This is Aztec. He is a good dog! He has been my son's companion for 14 years. He was soon joined by his awesome wife and joyful daughter. They are a beautiful family that also includes Dally the dog, and Ash the cat. Aztec, as he aged developed tumors on his hind leg. It was unsuccessful to just remove them, as they came back. After consideration of the cost involved and Aztec's age, it was decided to amputate the leg. He recovered quickly and has healed and has a much better quality of life. He has a ramp to help up the steps, but rarely needs it. 
I had been talking to my son about Aztec's recovery and he mentioned that the cost was over $5000.00! My first thought was to send them as much as I could afford. I could not afford to help.
My son and his wife were just getting out of a financial hole many often find themselves in. They work hard, both work and my son homeschools their daughter.

Any size donation would be greatly appreciated.