I have a male senior friend (87) who has chronic and severe UTI. He is also hemiplegic from a stroke. Recently, he became incoherent and agitated, so bad that I called 911 to take him to the ER. They determined that he was only severely dehydrated and was kept over-night for observation. Ten days later he passed-out, and again I called 911 to take him to the ER. This time they admitted him for UTI. I believe that they missed diagnosesed the first time, and claims should have handled as a hospital readmission.
Another previous time, I knew he an UTI, I took him to the ER and they treated him with an IV antibiotic. At 8pm at night they released him to go home! I thought that was a bad idea and pleaded with the Doctor three times to keep him for observation. The doctor said no because vitals were good. I gave up, took him home, and the next morning he awoke with a fever. I call 911 to take him back to the ER, and he was re-admitted for the UTI.
Couple years ago I was at the ER for a UTI which was common after kidney stone surgery, which was outpatient. I was placed in "observation" for 3 days until the lab could determine what type of infection it was, apparently there are numerous ones... thus, to use the best antibiotics for that infection. Today, I probably would have been set home to wait out the results.
It does not sound to me as though the hospital CAUSED the re-admission. Your friend from under observation and re-hydrated. 10 days later he developed a UTI. Why do you think those two things are related?
If he has chronic UTIs, is he being seen by a urologist? Is there a care plan in place, and does HE understand it? Someone with chronic UTIs needs to be mindful of hydration, hygiene and might be a candidate for ongoing medication and certainly regular UA to check for infection.
Is all that in place?