Toilet & Bathroom phobia. Her treatment.

My mother-in-law doesn't use toilet seat for urinating instead she urinates on the bathroom floor only. Neither she uses bathroom washbasin to wash her hands. Instead she used kitchen sink to wash her hands and face. I have never seen her going to the toilet in front of anyone. She has a very high sugar level of 200(fasting) and 350(after eating). She controls her urine for hours and hours but doesn't use toilet. If she ever goes to the toilet.. Then she takes a bath also after entering the toilet. She takes bath. for 2-3 hrs and doesn't come out of the bathroom in the morning. She keeps on washing all the doors, walls and even wooden beds and sofa sets with water pipe. She is not ready to visit any doctor.. Kindly suggest what shall we do in order to start her treatment.