Xbox banned account game sharing

Hey all, this question isn't for me but it's for sibling. Who, recently had their main account (which was also the main family account) banned permanently for no reason given. And then his 2nd account which he uses to play Fortnite on was given a 1 month temporary ban. Today he went on his 2nd account and tried to play games that he had bought on his main account. But, they won't let him play it. And with all the research me and my mother did. It was pretty much everyone and every official statement said that If an account get's banned. Other accounts on that console can access and play the games that the banned account had bought. But yet, this has happened. Please help me as my brother is not only still upset from the ban, but now with the thought of having to buy a LOT of games. It's making him feel like not wanting to play on Xbox anymore. So please can anyone help with this? Thank you

:)