What is the ruling regarding someone who is required to perform ghusl at dawn but bathing facilities are unavailable: should he perform tayammum and pray, or should he wait until they become available?

Whoever is required to perform ghusl (ritual bath) but is unable to do so due to the unavailability of water, or the inability to use it due to extreme cold or illness, should perform tayammum (dry ablution) and pray. He is not required to repeat the prayer if water becomes available later, based on the Almighty's saying: "And if you find no water, then perform tayammum with pure earth." Sufficient water must be provided for acts of worship, such as ghusl from janabah (major ritual impurity), as a Muslim is susceptible to nocturnal emissions during sleep.