I can understand the difficulties you are going through . The most common diagnostic condition of this presentation with old age, difficulty carrying out day to day tasks, incontinence and progressive course over period of 2yrs points towards Dementia but you haven mentioned any thing regarding forgetfulness . I would like to advice MRI Brain and get her metabolic profile done to rule out
Diabetes and Hypertension . I would also like to suggest you to visit a neurologist near by . For any further queries you can ask me don't hesitate