One Installation for 2 Accounts on one PC possible?

Hello, is it possible to use an installation on a PC with two users?

Constellation:
Father (game buyer) and son each have their own account on the PC. The son is registered with Microsoft via the family account.

As a father, I have now installed the game on my son’s account. I did this by first registering in the store and in the xbox app. After that, the game was downloaded. On a common hard drive of the two accounts on the PC.
Now I have logged out again and my son registered in the store and in the Xbox app.

Now we both have the game in our library. Is it now possible to play with one installation on both accounts on the PC?

Or do I, as a father, have to download it again now?

As a father, I can find the game in my list, but when I start it I always get the request that I should log into the app and store with my account, but then it doesn’t go any further.

Do I have to download 100 GB again so that I have the game? Then 200 GB of memory are gone for one and the same game.

It must be possible to manage two game accounts with one installation.

Is there a solution?

So an installation for two Microsoft accounts on one PC?

Regrads
Sebastian