What is the ruling on one who masturbates before the Fajr prayer and delays the prayer in order to perform ghusl, and what is the treatment for such a case?

Masturbation is forbidden (haram). Its prohibition and sinfulness are intensified if it leads to delaying prayer beyond its prescribed time. It is obligatory to offer sincere repentance and immediately abandon this habit, while striving against one's self and avoiding the causes that lead to it, such as dwelling on lustful thoughts or watching forbidden things. One must associate with righteous people, frequently ponder about Paradise and Hell, be mindful of Allah's constant watchfulness, seek His help, and supplicate to Him.