I would try another flavor and mix them at first. I wonder if there is anything else you could sprinkle on his food that he would be allowed to eat and he would like. I am not as experienced at this as some of the other PT people here so maybe someone else will have some good suggestions. I know what you mean, about loving him. I love all of my guys so much too and worry about them as well when they are not feeling well or won't eat.