I have this installed on my pc, Windows 10. My son has his own windows profile on the same PC. The issue is that the game wants him to download and install it as well.
So the question is: Do you need to have this game installed for each profile? If so that is a ton of hard drive space.
You need to log in to which account you want to use using the Xbox app. no need for 2 installs. Keep the Windows Store app logged into the account in which the game was purchased on.
All that will happen if your son clicks install on his profile is the license will be acquired for his account to allow him to play it, it wont be the whole game that installs.