I had a Yorkie that lived to be age 16, as he aged, he would cough and gag, like he was having an asthma attack. It happened occasionally, the vet told me that small breeds sometimes have narrow tracheas, that would cause the choking sensation and discomfort and possibly the gastrointestinal upset.
I don’t remember them offering anything in the way of treatment. This was a while back.
Maybe this is part of the problem for your dog? If so, it would have nothing to do with diet, however a soft diet might be best.
