How to restore legitimate iTunes purchases from a different Apple Account on iPhone 17?

So my husband traded out his iPhone 11 for another brand and now all the songs we bought on iTunes using his apple id are inaccessible. How do I restore these legitimate purchases to my iPhone 17? I have tried logging in with his appleid but it is no longer valid. Any help is appreciated.

[Re-Titled by Moderator]

Original Title: Lost iTunes purchases