There is a 911 forum page that might serve you better than this area..
But is it still actively bleeding? It doesn't vlook like it, but if it is you need to stop it. I'm assuming you don't have styptic powder on hand, do you happen to have something like corn starch? That can help clot it up.
If it's not still bleeding I'm not sure there is much you can do but wait to get him to the vet. They can assess it better, determine if it needs to be clipped or removed, and give pain meds.
Also if he is having trouble perching with it or repeatedly catching it on things maybe move him to a smaller cage to restrict too much movement and prevent more damage until he can be seen.
