As long as an infection doesn't set in, he will probably be fine. Several people on this site have chickens missing toes that are doing just fine.
Do you have any recent pictures that you could share?
It looks like frost bite to me, also. You might try giving him some antibiotics to work on the infection frm the inside out.
Soaking the foot would probably help with infection, too.
PM casportpony, she can tell you what antibiotics to use and what to soak his foot in.
Good luck!