Xdcool

Hey there, I need help, I want to make a series where a player is the final boss, and i want the wither skeletons to be like his soldiers and not attack him. I still want them to attack other players, and I don't want the final boss to be in creative because we can't kill him. I can't use mods either since I will be using a minehut server. Is there any way to make all mobs, or one type of mob, not attack a certain player but still attack the rest? That would really help!