I experienced bowels and bladder issues after treatment and it is normal. In time, it will improve! For some of us may never quite be as it was before treatment but it is manageable. After treatment I found that mushrooms, tomatoes, too many green veg, spicy food, onions, would send me rushing to the loo...I had to stick to a low fibre diet for a tad longer - not the best diet when trying to lose weight.
The urge to urinate every hour or more i remember vividly and it is normal. If I was traveling I would not drink any tea or coffee that day and in fact drink very little during the day as I was worried I would not make it in time to the ladies...I didn't want to get any UTIs either so would drink plenty as soon as I would get home...not ideal but it helped. Tea and coffee are diuretics so I started drinking herbal drinks and twinnings have such a great selection.
the itching could be down to the radiotherapy making the skin in that area a lot more sensitive.
hope it helps. I know there are some meds to help with what your mum is going through but I chose to do my healing - as I call it - the natural way.