What is the ruling on ghusl (ritual bath) for janabah (major ritual impurity) if some body parts were not reached by water, with the person performing the ghusl being aware of this, and he prayed in this state out of fear that his family would know about his ghusl, given that he is unmarried and practices masturbation?

Janabah (major ritual impurity) is not removed except by washing the entire outer body. Prayer is not valid unless janabah is removed. Whoever prays while still in a state of janabah must repeat all the prayers he performed with that incomplete ghusl (ritual bath). If a Muslim intentionally leaves a part of his body unwashed, he must repeat the ghusl or wudu (ablution) and repeat the prayer. The excuse of not wanting to inform family about janabah is not acceptable. Masturbation is forbidden, and a Muslim's fear of Allah must take precedence over his fear of anyone else.