It's just in style. Take him some mags if it will help or some pictures of hippies in the 70s. He is pretty sensitive. Mohawks were popular with some kids in the late fifties/early 60s. Hair styles come & go just like slang, clothing etc. I feel badly for you because it sounds like he is more angry that you won't do as he says you should do, than with your haircut. I would be interested to see what his hairstyle was like over the years. Perhaps the Mohawk tribes feel differently about it. If so, rethink where you are with this.