I had agrument with a transphobe

So basically me and freinds wich include Chris,Kirby and Jane are or chilling in fifth period when we’re supposed to be in six. At our school because the power outage happened.so any way my freind triston walks up to us and apparently knew that my friends, Chris and Kirby are trans.said that quote “a man can not be a woman” and I was pissed off at this remark my freinds bring up the surgery, another constructive arguments.but he just had the aame one. Btw who is he is a man to define what a woman is.