I think a lot of you don't realise that you can't 'share' steam games. Steam has something called Steam Families, which lets you share you games with 5 close people but that's as close as you will get to being able to play a game you didn't pay for. If you do use Steam Families, know that only one person can play the game at a time, you can't all use it. If you do not own the game, you can't play it. This is a smart move by myster as it stops all piracy.
Also don't ask/demand that
Koanao101 adds you to his steam family, I wouldn't add anyone who I dont know, especially as Valve notes that adult accounts can initiate password recovery actions or manage settings. So I don't think
Koanao101 would want to take that risk.
TL;DR: If you do not buy the game through steam, you can't play it. No one can share it with you.