What can I do about a child who freaks out everytime he gets his haircut?

My nephew is almost 4 and ever since he was a year old he's been impossible to give a haircut to. His mother is a hairstylist and he won't even let her do it! He only lets the stylist use scissors and even then he screams and cries the whole time. You have to hold him so you get covered in itchy hair (and so does he because he won't sit still). We take him to a place specifically for kids with cool seats like a fire truck and an airplane, they let him hold the water bottle, they have TV's at every station and nothing keeps him from having an absolute fit! There's just no reason for this behavior: he's never had a bad experience getting his haircut, he's just always been petrified of it. Any advice, PLEASE!!!