What is the ruling on masturbation for an unmarried person who does not want to touch a foreign woman, and what is the ruling on his ritual purity if he cannot perform ghusl due to water scarcity, and is tayammum sufficient for his prayer in this situation? And would he be sinful if he attended the washing and burial of his Muslim brother while in that state?

It is forbidden for a Muslim to commit a sin. If one dares to commit such a sin and then cannot find water, or is unable to use it due to illness or a well-founded fear of illness, then it is permissible for him to perform tayammum for his prayer, based on the generality of the Almighty's saying: "And if you are in a state of janabah, then purify yourselves. But if you are ill or on a journey, or one of you comes from the alleviation of a need, or you have contacted women and find no water, then perform tayammum with clean earth and wipe over your faces and your hands with it." As for washing the deceased or attending their burial, there is no harm in it, as purity is not a condition for washing the deceased or burying them; it is only a condition for praying over them. One must refrain from continuing and persisting in sins, and resist yielding to the self and Satan.