My mother-in-law has had a difficult several months. Falling and disorientation led her to be hospitalized, are we missing something?

It seems that she has suffered several UTIs which have resulted in classic elderly responses: disorientation, agitation, mild occasional memory issues. She was placed in an assisted living home after being hospitalized and then rehab. She seemed to be doing okay, but she "wings out" with becoming agitated, and exhibiting strange behavior like pulling all her clothes out of drawers and off hangers. Recently while in the assisted living home when the staff was doing an evening check, they found her on the floor next to her bed. She refused help getting back in bed and 911 was called. When the first responders arrived she tried crawling under the bed and cut her hand fairly badly. When she was brought into the hospital they tested for UTI and happily it was negative. She remained hospitalized until she was transported to another facility for rehabilitation, to encourage her to regain enough strength so she can return to the Assisted Living. (She has some physical issues with extreme pain in back and legs, which the pain meds have been reduced so as to rule out the cause of her "psychotic behavior." Things at rehab are not going well and they have not been able to get much accomplished due to her "cruising down the hall in her wheel chair, raising a ruckus at the nursing station, she has been removed from the dining hall for yelling, pushing her food around on her plate, wheeling into people. More details are not important, the point is that they do not feel that her remaining there is of any benefit. I concur. There is a request for her to be completely examined by a medical doctor as soon as possible. Here is my question: Is it possible that bacteria from the UTIs have traveled to her brain and are causing her irregular and frightening behavior. (We saw her just a few days ago and at first she seemed okay. Then she began switching her bed position, non-stop, maybe 20 minutes. Her PT for her came in for her session, she seemed to quiet a bit and focused; we left.) I am thinking, perhaps, we are missing something. Mom is generally a very smart, articulate and calm individual. She was a nurse. She will be 93