I agree with you, I think he is a zombie, or more like one of the people that have died and came back, hence the strange coloro of his eyes and his scars. So it's logical that he doesn't care of Teach wants to kill him, because he can't die and he loves Teach so muche he is willing to be "killed", even multiple times, as long as Teach's attention is on him and he gets to f*ck him.

What if he is a half zombie half human due to experiments, thats why he doesnt die and thats why he doesnt give a fuk if someone tries to kill him