During the course of treating and caring for my elderly Lab with cancer, I tried most everything. As far as diet, it’s commonly believed that a high protein diet devoid of grain, starches and sugars is beneficial. Grains, starch and sugar “feed” a tumor or so the holistic conventional wisdom goes. I wouldn’t know if it’s true, but my dog loved the diet, his coat came back in glossy and he was happy. The cancer wasn’t what killed him.
Check out tumeric. It is a spice that has been shown to shrink or prevent tumors. We give it to our dogs- they love it mixed with water and put on their food. One of our dogs has had several mast cell tumors and had to have them surgically removed. None since we put him on tumeric.
And sorry about the loss of your loved one.