Question about familiy library sharing

If they don't require Steamworks DRM, they can be played if started outside of Steam. Otherwise, when you start them up, Steam will tell you that you cannot run them any more.
Unless they changed something about it again.

Depends on the game . Most game wont start if you have cut the access to them , when they try to run them it will just land them on the store page asking them to buy them , but there are some who after installed work like a DRM free version of the game ( tho those are mostly cheap games , like RPGMaker ones ) .

So it is on a game to game basis , but solid portion of the games on steam do require a check if the guy starting it actually owns it in order to start them , so even if he/she kept them installed he/she shouldnt be able to start them

Maybe if he stayed offline for the whole time ? I'm not sure.

If you remove authorization to someone, then those games would still be installed but the "Play" button should instantly change to a "Buy" button. If you try to get around it by having them play the game while you de-authorize it, it should kick them out of the game within 10 minutes. One of the only ways around family sharing restrictions was when I refunded a game, but my brother was able to play it for a full 24 hours after I no longer owned it. Other than that, it usually seems fairly airtight with its restrictions.

Thanks for the reply and help guys, appreciate it