Is it permissible for a bedridden person who is unable to perform ghusl or change clothes except during the day to perform wudu and pray Fajr after a wet dream? And what should he do if that is not permissible?

Whoever experiences ritual impurity (janabah) must perform ghusl (full ritual bath). If one is unable to perform ghusl due to lack of water or inability to use it, they should perform tayammum (dry ablution) and pray. This includes someone who has a wet dream and fears illness from cold water, or if water is far away. A sick person who cannot wash their entire body should wash what they can and perform tayammum for the rest; wudu (partial ablution) is not sufficient in place of ghusl. Semen is pure, so it is not necessary to wash clothes stained with it.