Is it permissible for a friend suffering from multiple sclerosis, who finds it extremely difficult to perform ablution and move to enter the restroom by herself, to perform tayammum for prayer, even though water is available and does not harm her?

If the aforementioned woman finds someone to perform ablution for her, even for a fee, she should do so. If she does not find anyone to perform ablution for her and is unable to perform it herself, she should perform tayammum, because it is a substitute for water purification for those who lose it or are unable to use it. If she is unable to perform istinja' herself and does not find anyone to assist her, the obligation of istinja' is waived for her.