and welcome to the forum !
I have a few questions for you:
- When was he last seen by a Vet?
2. Exactly what do you feed him?
3. Has his appetite diminished since the vomiting started?
4. Since you've had him, has his drinking increased over time? When did that increase begin?
5. When did the vomiting begin? How often does he vomit?
6. Has there been any change in his bowel movements?
7. Any change in his urination patterns? In the amounts of urine deposited?
8. Does he go outdoors?
9. Do you have a Vet that knows him? Any Vet at all? Is that Vet a cat-only Vet or a general practice Vet?