Hello, Nathan!
Welcome to the Disney Parks Moms Panel!
First of all, I am so sorry to hear that your friend's Mom might not be able to join her family for their upcoming
Walt Disney World vacation. I am "wishing upon a star" that this will not happen, and she will be able to join her family for their MAGICAL vacation.
I wanted to let you know that your friends will NOT have to cancel the
Disney Dining portion of her reservation. Because Disney Dining entitlements are not assigned individually, your friends will have no issue at all dividing her dining entitlements between the other three family members. I also verified this information with a Cast Member today.
If you or your friends have other questions, please let us know. Again, we do hope that everything will work out for your friends to experience their Walt Disney World vacation together as a family!
Have a MAGICAL day!
Wes