In the last months of Muffin's life, she wouldn't eat dry food or the canned equivalent. I was getting desperate, because I wanted so for her to eat well. She always loved to eat. One evening I picked up some Little Cesars dog food and she ate like a little pig! I didn't care if it wasn't the best thing in the world. I just wanted her to eat. She loved it and ate it the rest of her days. I don't know if their taste buds are like older humans or not, but I suspect that they are and sometimes things with more flavor taste better. Muffin would eat maybe a meal or two of boiled chicken or boiled chicken with rice and then turn her nose up at it. Muffin's favorite Little Cesar meal was Filet Mignon!
If your little one likes fruits, have you tried mashing them? Don't know if that would help, but sometimes it does. I had a little chihuahua that lived to be 17 and in her last days we fed her liquified baby food in a dropper.
Another thing I did with Muffin was to feed her off of my finger because she couldn't see well anymore. I would put her in between my knees on the floor and she loved it. Let us know if anything works.