It is obligatory to use water to remove the state of ritual impurity in winter if one can heat it

Q: My mother is incapacitated and aged. Living in a cold region, she cannot perform Wudu’ (ablution) especially for offering Fajr (Dawn) Prayer. Is it permissible for her to perform Tayammum (dry ablution with clean earth), bearing in mind that she deems her Salah (prayer) defective when she performs Tayammum and, therefore, repeats it after sunrise?

A: All praise be to Allah Alone, and peace and blessings be upon His Messenger, and his family and Companions. (Part No. 5; Page No. 341)  Water must be used for Taharah (ritual purification) in winter if there is the ability to heat water, in which case Tayammum is invalid.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions!