I would bring it up if it happens again.

Also, the student loan thing isn't a big deal with how cheap BYU tuition is. I would be a lot more concerned if they were being unwise with the loaned money. I had a couple buddies max out their student loan applications to buy a wakeboat to party on all summer. Now that was stupid. If your daughter and SIL really are using the extra time to do well in school I'd say more power to them and it will pay back in spades