I almost have a micro. The best advice you can give him is that if he concentrates on his foreplay, he can do very good. I did. You can change his life if he gets a "Black Belt"
My wife noticed the results right away. He has to watch videos of lesbians, read men's articles that explain to you things that you would never know. Did you ever know why girls like to kiss a lot before sex? Because there are a ton of stimulating nerves on the top lip only that get them aroused. There are other places with high concentrations of nerves. The inner thighs are incredibly important.
But two thing happen that combine to help both partners out. The girl starts thinking that the guy keeps touching the right spots. Then she starts thinking that this guy knows what he is doing and its good, Thats a game changer,
Meanwhile your micro friend get's new self-confidence because ,like a surgeon, he knows the girls anatomy and how to touch it.I use to be a moderator here. I just found my old user name. It was Penis B Little. I posted tones of stuff for guys like me.
Finally talk walks, My ex was a model divorced in 1987. Married my wife 1989 and she has been called a 10 by guys. Today she is 52 and she still looks good. Communications love and understanding made our marriage work. In bed my work, her flexibility kept us happy, She was allowed to use a toy if needed. But now that I am 59 with certain illnesses , if the marriage was built on sex as the main foundation, she could leave me in a minute. But she takes care of my MS like disease in my legs. And if I start feeling a bit insecure,normal for a guy in my position, I simply track her cellphone on Google.Which I rarely do because she is always where she is supposed to be.
Please encourage your friend with all I have learned,