Ask him, or pose the question with your main, or do what most people do work out from stats or scout someone. Disclaimer - I can't be held responsible for an incidents resulting from any advice given matter how inane.
OP, I suggest you either ask him, or you try and input what you think his/her build is into the KaW Build Calculator ( viewtopic.php?f=6&t=141354 ), which would then tell you what her/his build is. Thanks mate.