Sharing Minecraft via Family Account

I purchased Minecraft under my Microsoft account and want to allow my child to access it via their account using the same laptop. They are set up in my Microsoft Family Group and I cannot see the purchase anywhere other than in my account. Web searches say they just need to log into their Microsoft account, go to the Microsoft store and download it, but this just tells them to purchase it again, when it is already downloaded on the laptop and accessible when I log on as me. Please tell me what I'm missing.

:)