OP - No operating business, including an air carrier, is going to start tossing "compensation" around in a situation where there might be a lawsuit.

If UA has a crystal ball and knows that MIL just wants a couple of miles and will forget about it, they would do that in a heartbeat. But, they aren't going to acknowledge liability by tossing miles unless they have a full release.

Unless there was some unseen injury which later became evident, this should have been reported on the spot and written up. If it wasn't important enough to report, it's not going to draw much now.

Additionally, if it had been reported, a UA supervisor would have met the aircraft and you would by now have heard from some claims adjuster type.

Lastly, unless MIL can't read & write English, she needs to do any complaining. Otherwise it kinda looks like the greedy relatives.