Is it permissible for someone who inherited money from his deceased brother through insurance to perform Hajj on behalf of his deceased brother with it, or should he leave it for his minor children, or invest it for them?

The deceased's written nomination of beneficiaries for an insurance policy is not considered a valid will unless acknowledged by the adult heirs. Some scholars, such as the Hanbalis, have held that a will written in the deceased's own handwriting is valid. The bequest is valid for you because you are not an heir, whereas it is not valid for your wife unless all adult heirs agree. The deceased's participation in insurance is permissible only if it is cooperative. If he was compelled to participate, he is only entitled to what he paid, and the excess is not due to him. If what he bequeathed to non-heirs constitutes one-third or less of his wealth, his will is enforceable. If it exceeds one-third, the excess belongs to the heirs. You may dispose of your share of the bequest by performing Hajj on his behalf or investing it for his children.