Here is how Southwest works:
Wanna Get Away Fares (technically non-changeable) are both changeable and cancellable, but the hitch is that the funds stay under the original traveler's name. Also all travel must be completed within 12 months of the date that the original fare was booked, not the original date of the actual travel. So if the flight is cancelled, you would then have however much money was spent on the original fares to be used within 12 months of that booking date. But the amounts spent are then tied to that traveler's name, so those funds can then only be used to re-book those same passengers, they cannot be used for someone else's travel. So, as long as they do plan to take some sort of flight within the next 12 months you should be good.
Anytime fares and Business Select fares are both totally changeable and totally cancellable and the funds will go back to the credit card with which they were paid.
Let me know if you have any other SW questions...I have flown them weekly for 3 years so I have encountered just about every scenario there is.