Me and my brother would like to play on different profiles in GTA V (pc). Can this be done?
You can each save the game in separate save slots, just have to be careful when telling the game which save slot to autosave in every time you start the game. The game will also automatically load the last played save file, so to switch, you'd have to load the game and then manually load the other saved file.
Since the GTA V profiles are saved in the documents folder, you could easily have separate profiles and save files/slots by using separate Windows accounts.
The first commenter is right about the save games only regarding offline.You can have many save games. You cannot have 2 GTA online profiles without buying 2 copies of the game or buying a second product key from Rockstar, because the product key is single use only for one profile and one Rockstar Games Social Club account. Your brother would have to make his own Rockstar Games Social Club account, you would activate the new key that you purchased on his account then you can both play online on separate profiles. I hope this helps.
iirc you can set up family profiles on Steam, allowing another profile to play the parent profiles steam library from the same machine only. https://www.cnet.com/how-to/how-to-share-your-steam-gaming-library-with-friends-and-family/