Is it permissible, in Islamic law, for a mother to distribute gold to her daughters before her death, especially given that both the father and mother do not object, and is it obligatory to inform the husband of this?

The nature of the mother's action must be verified: did she gift the gold to her daughters during her lifetime and possession, or did she bequeath it after her death?

If it was a gift and possessed before death, then the gold belongs to the daughters. Otherwise, it reverts to the estate.

If it was a bequest of gold to the daughters, then, in principle, it is not permissible due to the Prophet's (peace be upon him) saying: "There is no bequest for an heir," unless the heirs permit it, in which case the bequest is executed. If one of the heirs, such as the husband, does not agree, then his share of the gold must be given to him.

As for the inheritance of the daughters, it is their property, and the father may dispose of it as their guardian and spend from it on them. He must hand it over to them when they reach maturity. The father may take from his daughters' wealth for his needs without extravagance, but he does not own the wealth merely by being their father. The meaning of the Hadith "You and your wealth belong to your father" is permission, not ownership.