Hi BCT3!
My name is Shakiru, I'm an independent advisor and user just like you, and I'm happy to help you today.
I understand that you cannot share your family Microsoft 365 subscription with other people.
Do you still have an active Microsoft Office 365 subscription in your family? Go to https://account.microsoft.com/services.
If sending an email invite doesn't work, you can try adding yourself directly to a member of their family group and then sharing it with you
See Eileen Gal's comment on how to add you to a family group: https://answers.microsoft .com/thread/e90be893-1079-4b40-b69c-33687871c88e
Details on Microsoft Office 365 Family subscription sharing can be found here: https://support.microsoft.com/office/b389b9ce-3ae3-4a82-9017-39d79972fcba
I hope this helps! Please let me know if you need any other assistance and I will be more than happy to help further.
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Thank you
Best Regards,
Shakiru