What is the ruling of Islamic law regarding a grandfather distributing the inheritance of his deceased grandson, and singling out one of the heirs for an increase, and what is the religious ruling on depositing money in banks?

First: Your father does not inherit from his father because he died before him. However, your grandfather inherits one-sixth of your father's estate due to the presence of a lineal descendant (you). The remainder is divided between you and your sisters, with the male receiving the share of two females.

Second: Your grandfather's distribution of his estate during his lifetime as a gift is permissible. However, if it is intended as an inheritance, it is not valid. The money he spent on you is considered a gift. If he bequeathed something to you, it is permissible to take it after his death if you are not heirs at the time of his death; otherwise, a bequest to an heir is not valid.

Third: Depositing money in interest-based banks is forbidden.