At the moment, I use Steam share to share with friends. As the game is a multiplayer game, will it be sharable, or will it blocked from Steam share?
I assume it’ll be sharable. But you won’t be able to play it all at once. Only one person can play it at a time. You and your friend can’t play it at the same time.
I’m aware of how steam share works, been using it for a long time now. 
It’ll work how every game on Steam works.
Not every game on Steam is compatible with Steam Family Sharing.