White vest on burgundy shirt on jeans is something i have seen at my local Express store. He also seems really slim, made me think of hedi's model casting.
As for the latter depending on where he lives, and what styles he likes, SF might just lead him down a path he doesn't want to really go down. Some dudes actually enjoy dressing in styles SF does not like and get a lot of love for it. If they want to be more into that style it would be counter productive to get advice from here. Like if he liked the super prep aesthetic and wanted to perfect it this would not be the place to go to, to do that.
Thats all i meant.