Potato del Grande
Is also solo time trial stuff with rivals challenges that is competitive but not online per se. Lots to do, including finding billboards in random places exploring.
i dunno how it works but can't you make his console your accounts "home" console and then he gets all the xbox gold/ultimate stuff when he logs in his account? You'd have to then login and be online on your own xbox to play games, but i think it should let 2 consoles share digital games, online access without paying twice, all gamepass games, etc
gamestop will be selling the $35/mo series X sub thingie where you pay for 2 years and keep the xbox and get gamepass ultimate
should go up at 7am PDT / 10am EDT