Why Does My Cat Keep Sneezing Blood?

Bloody nasal discharge can be a sign of feline upper respiratory infection, nasal foreign body, nasal tumor, or a traumatic event.  This cat needs to be examined by a veterinarian.  The treatment will vary pending diagnosis.

Because he needs to go to the vet.  I don't know what else to tell you but no advice you can get here is going to be of any use without knowing the cause.  Sneezing blood is probably a good indication that professional help is needed.   Stiff the vet on the bill if you have to but get the cat treated professionally, there is no excuse.