My Friends Cat Is Vomitting Blood And Dies Then Comes Back To Life, What Could It Be?

The cat sounds like it's bleeding internally, I'm sorry to say.  If you can find an emergency veterinary service in your area, please call them, or try to get the cat there as fast as possible.  The cat is losing blood, and that is why it's losing consciousness.  If too much blood is lost, the cat is going to pass on.  I'm so sorry that this is happening to your friend's cat, and I hope by some miracle that it can be helped out.  The cat may have punctured it's stomach lining, or some other part of it was hurt, but your best bet is to try and find a vet doctor that could at least give you some advice.  
I sincerely hope that you can find someone to help you out tonight, and again, I'm sorry I can't give you better advice.
Moe

One life down and six left to go.