I'm not familiar with Felidae, but I am familiar with the constant vomiting problem. Some of the cats that have gone through the shelter have had this problem and the vets put them on sensitive stomach formula. Either Science Diet, Purina, or Eukanuba. I'm not sure why it works, but it did for several kitties.

When you take Ash in for his check up, you might ask about it unless the vet thinks its allergies.

Hope he gets an A-OK!