How to ensure continuity after subscription plan lapse?

My sister has used Lightroom Classic to edit thousands of photos over the course of many years. Three years ago she needed to replace her PC. She's not technical and paid a consultant to help. He installed Lightroom Classic on the new PC, telling her the license cost was $10. She doesn't use cloud storage - all her photos are on her hard drive, with some backed up to an external HD - and she didn't realize that she had a subscription plan that needed to be paid every month. She received popups, but they were unclear and looked like spam. Finally on September 3rd she received an email from Adobe that we've verified with Adobe is genuine, saying that her plan was cancelled due to non-payment, and she has 30 days to sign up for a new plan, or they will delete all her data (we discovered that a small percentage did sync to the cloud three years ago when she first got the subscription) and her software will get deactivated.

Her main concern is that Lightroom Classic continues to function and she continues to have full access to all the existing photos and edited photos on her hard drive after October 3rd. It would be best and less stressful if she can continue to use her existing installation of Lightroom Classic 11.5. We've spoken to Adobe support a few times, and the one consistent thing they've said is she'll need to sign up for a new Lightroom subscription plan. But we haven't gotten a clear and consistent answer about whether all her photos and edited photos will continue to be acceptable, whether the existing Lightroom Classic installation will continue to function, and what, if anything, she needs to do to ensure these things, beyond signing up for a new Lightroom subscription plan before October 3rd. Any guidance on these questions would be very much appreciated.