I can guarantee that no one who is a member of this forum can tell the difference between a button buck and a doe at 215 yards......unless they were using the HUBBEL Telescope!
It's difficult enough at 50-60 yards and thats even with the deer making u turns in front of you to try to tell their sex from 'behind'....
There's always a 50\50 chance of being right or wrong and we've always been taught that on young deer, it's safer to pass than be completely wrong.
I wouldn't worry about his decision to shoot. I would be happy for his success and use the experience as a teaching\learning tool.........