You dont have to follow everything he suggests, but it will be invaluable to help you avoid some of the most glaring mistakes you have made.
For instance, if you've written a man who thinks about sex every sentence your guy friend can let you know that they really don't think of sex THAT often.
Or if you accidentally show your male obsessing about whether someone thinks his house is clean enough… your guy friend might read that and ask "do people really worry about that much?"
Or other ACTUAL mistakes you might be making. Very few men can write a woman who actually acts sensibly… and very few women can successfully write a man who actually thinks like a man.
Both genders tend to write the opposite gender with either too much of their own gender(if theyre being kind) or a lot of misogyny/misandry. Women either write a very feminine man or a very stupid bullish one.
So consulting with a man you truly respect can help you avoid those errors. And if you need your male character to do a certian action… your guy friend can help you find a motivation that reads as real to a male audience.