For a lot of games you can simply copy out of Steamapps/common and run the exe and it'll run like a standalone copy. For games that use steam features, you can

For a lot of games you can simply copy out of Steamapps/common and run the exe and it'll run like a standalone copy. For games that use steam features, you can drop in a steam emulator[0] to shim the API calls. I use this for when I want to run multiple versions of the base game with different mods. Typically this works fine as long as there's no real Drm/anticheat (which is common in multi player games but rare for single player). So this should allow you to clone parts of your library for your son to play (as well as consolidate your many accounts). [0] https://gitlab.com/Mr_Goldberg/goldberg_emulator/blob/master/README.md https://gitlab.com/Mr_Goldberg/goldberg_emulator/blob/master...