PLEASE HELP ME - VET NEEDED/someone who knows about cats

My cat who is 20 years old in human years has like a really black nail thing on his ankle, well just near the bone on the back of his paw, and 2 weeks ago he just lost one, it looks like its been ripped out and a few days ago we noticed its happend again on a different paw.

However the first one has gone really bad and its all red and saw and a bit of fur is missing, its about the base of your thumb big were the fur has gone, and the base of your tiny finger where the red saw thing is, he does have fleas.

We've got no idea how hes done it, we never let him outside because of his age and he would get lost with his memory and he stays upstairs where I always am if im not out on the actual stairs, but 2 nights ago hes been with me all the time since then, like sleeping in my bed.

Hes 20, the vets is about a 10 minute drive away but hes just so old he might have a heart attack or something, please help me, i love my cat so much and want to know whats best.

Thank you.
- Mike

Simple, take him to the vet. He won't die, cats don't normally get nervous, they get annoyed at being in a box. It sounds like a tick, but if it is causing a rash you'll need a vet, no advice will help.