What is the ruling on an elderly person not performing ghusl for over a month due to the cold, despite the possibility of warming the place?

If a man is not in a state of major ritual impurity (junub), he is not required to perform ghusl (ritual bath). However, if he is in a state of junub, ghusl becomes obligatory for him as long as he finds water and is able to use it without harm. Old age is not an excuse to perform tayammum (dry ablution) instead of ghusl, and his fear of cold is unjustified if he finds hot water, because jurists have made ghusl obligatory in this situation. Ibn Qudamah said: "If he fears extreme cold, and it is possible for him to heat the water, or to use it in a way that he is safe from harm, such as washing one limb at a time and covering whatever he has washed, then that is obligatory for him." Therefore, tayammum is not permissible when one is able to use water.