When we noticed that my Mum was smelling we realised that it was incontinence - stale urine smells! If that is the case an appointment with the GP (with your Mum?) or a call to the surgery to ask to speak to the continence nurse and they will help you get free pads which make ALL the difference. That is if it is urinary incontinence and it does sound as though it may be but she will need some help adjusting to using the pads and reminders etc, Good luck