Sickle Cell disease does its damage by blocking tiny blood vessels. The cells are too large to pass through, so they block the passage of needed red blood cells. The blockage often causes pain episodes. It can damage internal organs, and often causes stroke, even in children, by clogging blood vessels to the brain.
I'm not a medic, but obviously, you don't want to beat up a patient with anemia. A beating would immediately make it worse from internal hemorrhaging and bruising. I should think it could easily be fatal.
Wouldn't his family have known that he had sickle cell? I thought it was one of many things that are tested for when babies are born. Maybe I'm wrong, and am confusing it with some other disease. I did a research paper on sickle cell a bazillion years ago. I guess I should look into it again. I thought the signs of SCA were very apparent during childhood.