Mum had faecal impaction. I was told this stopped her bladder emptying properly hence the infections. When the bowel overflowed, the impaction was still there and she ended up in hospital with sepsis. It may be the catheter is there to make sure your mother's bladder empties, but she's getting infections anyway. I know every case is different, so what's caused all this with my mother isn't going to be the same as with yours, but I'd be asking why hasn't the hospital given her an enema or even enemas to clear the impaction? If they don't want to give enemas, why don't they and what are they going to do about the impaction? It's dangerous.
It is very hard indeed to deal with this without back up from family to add their voices to yours. It is so painful watching one's loved ones going through this appalling treatment. Best wishes.