Is there any therapy for post UTI delirium?

Once the UTI clears up, so should any symptoms it caused. Its possible the infection is still there, that the antibiotic used was not effective. I would get the person tested. If found that the UTI is still present, I would make sure a culture is done to determine what antibiotic should be used. Most of the time they start out with a broad spectrum one that doesn't work.

Make sure the person drinks plenty of water. That they void completely. This may mean sitting on the toilet a little longer and leaning forward to help in voiding completely. Cranberry tablets and a probiotic may help. But as suggested, you need to call the persons doctor.

This is a question for her physician. We are not doctors, plus there are too many other variables that may be at play, like whether she was hospitalized and for how long; what antibiotics she was given and for how long; what other medications she was on at the time and is still on; whether she is now getting enough hydration and nutrition, etc. I'm so sorry you are going through this with her. I wish you success in getting answers.