We are minding a cat long term, we have had him 6mths now. Our own cat beats up on him. He regularly gets stress induced cystitis and we have to visit the vet. He usually gets an antinflammatory injection and this fixes him but burns the $$. Can anyone recommend something that I can get over the counter, either to relieve his stress or the cystitis? Both cats are desexed males 3 years old (ours) and 4 years old.