I'd gauge his reaction to asking questions about his perceived attractiveness towards women. If he says some bluepill shit like a winning personality, loyalty, honesty, etc. you might as well rip the band-aid off and drop some black pills. don't gotta be insulting, just be frank. he's going to have a very hard time attracting a girl, will face constant rejection, and even if he lands one he will be cheated on. best to stick to the first two because the possibility of him of him getting something in the first place is nil.
explain it's a trade off. he can go into the wilderness blind, get painfully shot down, be friend-zoned for decades, lookmaxx but never overcome his height or face, and be gaslighted by women who says he just needs to find that girlfriend and they would totally date him if they didn't have their 6'4 bf teehee, or he could know the painful truth now and decide if it's worth the effort. the truth will set you free but not everyone can deal with freedom.