What should a person in the state of janabah do in the event that s/he cannot find a suitable place to have a bath?

A junub person who cannot find water to have bath, thinks that s/he will get sick if s/he performs ghusl in cold weather, or cannot find a suitable place to perform ghusl establishes his/her prayer by performing tayammum. Because there is a situation that necessitates it (Marghinani, al-Hidayah, I, 173,174; Mawsili, al-Ikhtiyar, I, 82).

Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS

Is A Person With Mental Disability Obliged To Perform Ghusl?