Is merely informing one's husband about a will to donate a third of one's wealth in the path of Allah sufficient, without taking any other measures?

There is no harm in bequeathing a third of the inheritance for charitable deeds; rather, it is commendable, as it is authentically reported from the Prophet (peace be upon him): "Indeed, Allah has bestowed upon you as charity a third of your wealth at the time of your death, as an increase in your good deeds." It is also commendable to write it down and have witnesses to it to prevent its denial, based on the Prophet's (peace be upon him) saying: "It is not right for a Muslim who has something to bequeath to spend three nights without having his will written down with him." It is obligatory to withdraw funds from usurious banks and repent to Allah.