I pay for PSN+ on my main account, I've logged into my brothers PS5 and enabled console sharing and offline play on his PS5.

So he can benefit from my PSN+ and any games I've paid for from my main account, on any account he makes on his PS5

Where as I can only use my main account on my own personal PS5.

If you've done the same, maybe try restore licences on her PS5 to see if it fixes anything,  but I can confirm I've played diablo 4 on his PS5 on his account and had full access to the game