C.C.
Have they swabbed the cuts to see what the infection is being caused by? My husband had a similar issue where he first had an infection with a cut he received while playing rugby (so really it would have been any number of vile and nasty things that caused it). They gave him some antibiotics and the infection seemed to go away. Well, then a few weeks later he gets another cut... big oozing infection. It turned out that he had a staph infection, and the antibiotics had really not affected it at all. His own body had kind of fought it off, but had not completely killed it. So the next cut he got, the infection reared its ugly head. He ended up on some really strong antibiotics once they finally figured out the cause.
My suggestion, if they haven't already done so, is to have them swab the infected area and send it to the lab to figure out what you're dealing with, and then make sure they give him the appropriate medication to deal with it. If the labs come back inconclusive, maybe ask for blood tests. It doesn't seem normal that he should have so many infections, so I wonder if it's just one infection or issue that has never quite gone away.
Good luck! Let us know what happens! Poor little guy.