10yo son wants to grow hair out, dad says absolutely not

Our 10yo has always had simple buzz cut, but now he wants to grow his hair out down to his chin a la Kurt Cobain. My ex (his dad) told him to forget about it. He's sort of like his "trophy" son and told me he would look stupid with long hair and messy. The funny thing is that dad is pretty unkempt and messy himself. Is this worth fighting over? via /r/Parenting https://ift.tt/339XnRV