@Stephenie16 Very sorry for the loss of your mom.
If you are able to access the account that was used to book, there is a fairly straightforward approach available: write directly to the host in the message thread to explain the situation and ask if they are still willing to honor the booking. They most likely will be, but technically they have the right to cancel without penalty if they prefer not to accept what is now effectively a third party stay.
If you don't have access to the user account, you're better off asking customer support to contact them on your behalf and perhaps creating a new booking linked to your user account.