i agree with all of the above
I am not a doctor but I can tell you this with absolute certainty.
This condition can be fatal. He probably has ruptured esophageal varices (associated with cirrhosis of the liver). The bleeding must be stopped and this demands immediate treatment. This situation will not improve without medical attention and I only hope that he is in the hospital by now. If he is not at the hospital please - get him there ASAP.
Joining in here, mikesimon is absolutely correct . Throwing up cups of blood is an emergency whether one has HCV or not, but with HCV it is much more critical. If you google "bleeding varices" you will see that without medical care this could result in bleeding to death fairly quickly. If he is still alive today he is lucky, but without treatment of the varices (banding is the usual treatment) they will bleed again and very likely be fatal. He needs medical care ASAP, and he is far from being "fine". I would suggest going into the ER even if the bleeding has stopped because otherwise it may take too long to be seen and this does call for immediate evaluation. If you can't persuade him then I would contact his family to see if they can talk sense into him. Thank you for being such a caring neighbor.
Oops, I didn't even notice this was the expert forum until after I posted. I'm not a doctor, just a concerned cirrhosis patient who recently succeeded in eliminating her HCV.