"Elderly people with serious urinary tract infection don't exhibit the hallmark sign of fever because their immune system is unable to mount a response to infection due to the effects of aging. In fact, elders often don't exhibit any of the common symptoms – or don't express them to their caregivers.
UTIs in the elderly are often mistaken as the early stages of dementia or Alzheimer's, according to NIH, because symptoms include:https://www.agingcare.com/Articles/urinary-tract-infections-elderly-146026.htm
My mother always recommended cranberry juice or cherry juice. And mothers, at least mine, are always right.