There have been many descriptions of an aging loved one overusing toilet paper. Any helpful solutions?

Limiting the amount available is probably the best option. If she is plugging the toilet then you can disconnect the chain in the tank so she can't flush it. Both options are a PITA.

In our house it turned out to be a short phase. It only lasted a couple of months. In the mean time, buy the cheap stuff at the discount stores.
Oh, and since her phase is over now I have the problem of her cleaning herself after using the toilet. But when I remind her, she will wash. Sometimes using the towels, even though we have wash cloths for her to clean with.