You are going to have to cut it off below the dead and infected area and then spray anticeptic on it and bandage it up. My little cuz had a litter of kittens, once older they hid everywhere. One got in the truck engine and got about half its tail cut off, we cleaned it up, sprayed it, and bandaged it. Now this will be very hard to do since cats can be very mean. My grandpa castrates male cats by sticking them in a boot so they cant scratch or bite but that is a hard thing to do all in itself. You will have to cut inbetween the bones and try to keep it as close to the infected are so it will still have alot of tail for balance. I wish you good luck and tell us how it went when you are done. It shouldnt hurt the cat to bad, maybe for a few days, just like docking baby sheep or dogs , bye
