Please note that this is a user-to-user community. As moderators, I have limited access to internal development details. My role is to direct users to the appropriate support channels and resources. While I cannot provide backend analysis, I will do my best to assist you within my responsibilities.
I’m so sorry your mum is going through this. Since her recovery info is outdated, the best next step is to submit the Account Recovery (ACSR) form for her Hotmail: https://account.live.com/acsr (fill in as much as you can—old passwords, folders, recent subjects, known contacts, and try from a device/location she used before).
If the form doesn’t verify her after trying, please contact support so that a live agent could further investigate the case:
- Visit Contact - Microsoft Support
- Type a brief description of your issue in the search box
- Scroll down to the bottom > select Sign in to contact support
- Log in to another available personal Microsoft account.
- Under Products & Services, select "Other Products"; Under Categories, select "Manage account security", and click Confirm.
- Click "Chat with a support agent in your web browser" (during business hours)
I can only provide guidance to facilitate the recovery of your mom's account, because community support cannot directly help recover the account, thank you for your patience and understanding.