What is the ruling on opening an account in the wife's name for investment and saving money in it, so that it will be for her and the children in the event of the husband's death, such that other heirs do not share in it?

It is permissible to invest money through the wife's account, provided that the investment is in permissible matters and legitimate stocks. In the event of the husband's death, all that he leaves becomes an inheritance to be distributed among the heirs according to their legal shares, and the fact that the money is in the wife's name does not make it permissible for her to seize it without the rest of the heirs. It is permissible for the wife to gift some or all of the money while the husband is healthy and of sound mind, unless the intention is to deprive the heirs, in which case it becomes forbidden, and such a stratagem is considered unlawful.