Is the gold left by the mother for her son considered a bequest or a gift, is zakat obligatory on it, and is it permissible for the sister to dispose of it before her death?

Gold is not considered a gift to the son unless he takes possession of it, nor is it a bequest to him unless the mother explicitly declares it, either verbally or in writing. If the mother declares it as a bequest to her son, it is a bequest to an heir and is not enforceable without the consent of all heirs. If there is no bequest, the gold is returned to the estate and divided among the heirs. Zakat is obligatory on used jewelry. Whoever omitted it due to ignorance or following a tradition is not liable for what has passed, but it becomes obligatory upon them from the moment they learn of its obligation. If the bequest is proven and the heirs approve it, then the gold is the son's property and he owes Zakat on it. If it is not proven, then the share of each heir is considered; if it reaches the nisab, Zakat becomes obligatory on them.