Sounds to me like he has a bleed. Throwing blood at it is just a temporary fix. He needs to have a scope to see exactly where the bleeding is coming from and how they can get it to stop. You can't go on with a GI bleed like that forever. Get him to a GI doc and schedule that scope.
The same thing happened to my great grandmother. She has been in and out of hospital for blood transfusions and they told us she had to be bleeding from somewhere inside they didn't know where. Did a bunch of tests and found nothing. They would get her feeling better and send her home and a couple months later she'd be back in getting more blood and iron and all. After about 6 months or so of in and out of the hospital they told us she had a form of leukemia. Where the leukemia attacks and kills your red blood cells. As of now the fourth transfusion has been holding and everything is looking good. I don't know if they even know what's going on they just told us that to make us feel better. She is 91 years old. Sounds to me that if your dad has erosion to his esophogaus he needs to quit drinking alcohol. He may be bleeding internally from the damage the alcohol has done. My husband had a very serious drinking problem and he almost died from ulcers in his esophogaus. He had to have 3 blood transfusions and the drs. told him if he continued to drink he was going to die. No ifs, ands, or buts. They also told him if they saw him back in the er due to drinking they would not treat him due to the fact that they can stop the bleeding but if he wouldn't quit alcohol he would just keep ending up in the hospital due to all the esophagus damage he did. He had 3 ulcers on his esophagus. Please try to convince your dad to quit the alcohol or it will only kill him. It took the dr. to tell my husband if I see you back in here for the same thing I will NOT treat you and you will die. She saved his life. Your dad also needs to get on Nexium or some kind of acid reflux medicine that heals your esophagus so that this does not happen again. Good Luck!
This might help some, ask them if the can do a CT SCAN with contrast, if there is a bleed they might be able to see it, or they can do an artialgram something like that, it is where the go in like during a heart cath to look for it and fix it all at the same time. Also there could be another issue. My father has blood issues also, we have had transfusions, iron and other things, we found out that he has an enlarge Liver and Spleen. With both but this large the liver is constricting the blood flow to the spleen which helps to cleans the blood, so it sits there to long and in short, instead of cleaning it and pumping it out, it is eating red blood cells and some platelets. Hope this helps some, I am worried about my dad also, we are still awaiting more test. Good luck and God bless. Something else I would like to mention, is if he is losing it at a semi-fast rate but it is not exiting the body at the same rate his body will soon start to reabsorb the blood inside his body, and by giving him to much they can over load his heart, just be carful and ask as many questions that you can think of