Advice re. cat's ripped claw

Hi,

My semi-feral, very elderly cat ripped his claw, I assume, in the past 24 hours.

It is the last toenail on the outside & it's sticking straight up. He doesn't want me to touch it - there is no blood & he's only favoring the foot very slightly.

I'm wondering if I need to call the vet or if I can treat it at home. We have a mobile vet, who comes to the house, since he would freak out if I tried to take him anywhere.

I'd appreciate any feedback or experiences anyone has had with similar problems.

Thanks.

Liz