My friend can't get hard! 😮

Anna • Love music,and fitness and health and Nutrition! Have a wonderful boyfriend been together a year! Write and sing songs💖
So one of my best friends he met this girl and they were home alone and the got naked but he tried playing with himself and stuff but he couldn't get hard and so it ended up being a fail! And he was embarrassed cause he tried humping anyway but nothing worked?! Any idea what's wrong??Â