Online access in free 2 play games working

There are 2 types of memberships. Free (also known as Silver) and gold. Free members are can sign into Live and download content from the marketplace, but can't play online or access most apps. Gold members can play online, get early access to demos, get
discounts on content, etc.

It could be for 1 of 2 reasons. If the games you're playing are free-to-play, they do not require a subscription to play online. Otherwise, if someone else has your console as their Home and they have a subscription, you would be accessing their subscription.

There are 2 free games per month that you can download with Gold, but Gold is primarily used to allow you to play online. Game Pass gives you access to a library of games to play. Game Pass Ultimate is a combination of Gold and Game Pass.

Because with gold you can get 2 free games every month too. It’s not only online game access

You would need to have console A set as your Home console in order for her to continue to access your games/games from Game Pass as well as your Gold (the ability to play online) without you being signed in.

Fortnite is a free-to-play game so it would be free for her to download anyway and does not require a subscription to play online which is why that game still works.