Just a thought, perhaps some homeopathic remedy could help Killian's gengivitis. My 18 year old cat has a chronic gum problems (bad breath and when he sneezed sometimes there is a little blood), the vet said that, due to his age and weak kidneys we should not give him any drugs. He is not in any pain and eats normally, to help him along we give him homeopathic remedies to fight the gum infection. I also used it when I had a bad tooth abscess... It works slowly but perhaps it wuold be better than nothing. Moreover there are no side effetcs.