[anonymous]

Zignature for a high quality kibble. Mighty Dog canned food, just a little mixed in to make it tasty, plus add a little warm water prior to serving.

That’s what I would try, assuming medical/dental issues have been ruled out via vet exam and the dog does not have any dietary restrictions.
Some seniors do better on soft food only.
A friend has a 13 year old small breed that does well on Blue canned food.