Well, she says she'll go to the HW store and get a new one tomorrow.
I appreciate you guys (and gals) patience! It's frustrating to not be able to answer in details other than I do 'Mom-speak' quite well, so yes, it's the bowl and she's not hearing anything (her hearing is still tip-top). She's checked the tank (The other bathroom had a tank problem last year and we talked her through fixing it)
Yes, re-fills on flush.
I'm thinking vacumn pulling via vent sounds most likely just now but I'll have her give it another good go with a plunger and change out the flapper since those are simple cheap fixes.
The reason why I think it may be wind driven is 2 things recently changed the wind pattern. She put up a much better wind barrier and re-insulated underneath. She also mentioned a large tree was taken out fairly near her lot, just a little bit ago. That might be affecting any top venting.