Questions about family accounts in XBox

Hi,

Yesterday I purchased a new XBox for my son. I set it up quickly using my existing Microsoft account and purchased Minecraft Dungeons for him to play.

Then I installed the XBox Family app on my mobile device and started configuring a new account for my son.

Then when I tried to login to the XBox using my son's account he wasn't able to launch the game, as it asked him to sign in as the person who purchased it (me). So my first question is how can I share the application I already purchased with the new account
I created for my son.

In addition, each time I sign in with either one of our accounts to the XBox device, I need to enter the password for this account with the on-screen keyboard, using the controller. This is pretty logical, but there are 2 problems that bother me:

1. Entering a complete password with on-screen keyboard using the controller is pretty cumbersome and inconvenient

2. Whenever I enter my own password, my son can easily see which keys I enter and know my password. As mentioned before, in order to allow my son to play Minecraft Dungeons, I need to log in with my account... I also guess that I'll need to enter the password
once he'll want to purchase another game.

Note that I configured a passkey for my account but it still asked for my full password when I logged in to my account, so it doesn't seem to help. Am I missing something? Isn't there an easier way that to enter the full password each time one of us logs
in?

I'm not sure if this is possible, but what I wish is that my son (and possibly other family members) will be able to log in without a password (just choose their user, or at most require to enter a pin code), and whenever I need to authorize a purchase,
I'd like to do it from my mobile device. Is something like this possible?

Thanks in advance.

:)