Originally Posted by
kjnangre
No. The initial flight was cancelled. If she decided to go to Maui (or anywhere else) she would have to book a new flight herself, and she could pay for it with her credit. OP would have no control over that new ticket, and wouldn't even know about it unless she tells him.
He would if he controls her Skymiles account (I didn't read all the posts at the beginning to determine whether this is the case or not).