Mom is 90, sudden on set confusion and memory loss, due, we think to a uti. How long does it take for the "fog" to clear?

Whilst my father is 80, 4 weeks ago he could answer 90% of the general knowledge questions on the Mastermind TV programme! Now, after a severe UTI, he forgets his children's names. This is not normal progression old age memory loss and I am shocked at how an UTI can impair the mind to this extent and at such speed. The doctor assures us that after the antibiotics have cleared up the infection, he should recover in 3 to 4 weeks. I sincerely hope so!

Chiming in here...any luck using the Azo UTI test strips? I bought a box as I thought my mom might have a UTI. I can't really get the test stick between her legs and she uses a raised toilet seat. I was able to get my hand under the seat and blindly wave the stick around until it got saturated. But by the time I got my hand pulled out from under the seat, I think more time elapsed than I was supposed to count. Can't get a cup under the seat to get a clean "catch." Thanks for any feedback and all the good suggestions posted already.

My mom has been on antibiotic since Thursday night and this is Monday night and she is still in the foggy stage of an uti. She is taking kafflax(?) should we try another antibiotic? I think she went about 2 to 3 weeks before it was diagnosed at a nursing home while recovering from a pelvic fracture.

Did they do a culture to test for what kind of bacteria is causing the uti? If they do that, they can tell what antibiotic will clear it.

This information has been so helpful.
My Dad will be 95 in just a few days. He did not have to use any appliance to see or hear or help to walk. His mind was sharp and he took care of himself, the house and his wife. At 80 years old he was jogging 5 miles a day. 2 years ago he had a TIA that put him in the hospital for 2 days. He recovered quickly. In October of 2016 he had another TIA that was much worse than the first and kept him in the hospital for 2 weeks then a NH for another 2 weeks for speech and occupational therapy. Due to catheterization in the hospital he developed an undiagnosed UTI. He was home 6 hours from the NH when he collapsed and was sent back to the ER. They put him on antibiotics. He is in a rehab center at this point and can barely speak. On pureed foods.
I believe it should be a standard practice that before a patient is released from a hospital and has been given use of a catheter; they should be given a test for a UTI. It would improve the health of so many lives. If not a standard practice; remember to ask for a test before leaving the hospital!