She may need a different med or a combo to really help, if this med is not working.
She needs to confront her doc about this, it is not uncommon for some meds to have a "poop out" point, and with some meds increasing the dosage will not target the problem, fortunately there are various types and/or combos that can be tried under doctor supervision.
I wish you lots of luck with this, I understand how frustrating it all can be.

Take care,
DE