Is it permissible for a young man who is paraplegic and had a nocturnal emission to perform ablution and pray Fajr, given his inability to perform ghusl or change his clothes until daylight, and what is required of him if that is not permissible?

A person who is in a state of major ritual impurity (janabah) must perform a ritual bath (ghusl). If unable to do so due to lack of water or inability to use it, they should perform dry ablution (tayammum) and pray. Similarly, if one fears illness from cold water and cannot find a way to heat it, or if water is far away, they should perform tayammum and pray. Ablution (wudu) is not sufficient in place of ghusl. If one can wash only part of their body, they should wash what they can and then perform tayammum. Prayers performed without a proper ghusl or tayammum must be re-offered. Semen is pure, so clothes do not need to be washed because of it.