Should a son who manages his widowed mother's money distribute it equally among his siblings, and do they have the right to demand that?

The grant that the mother receives after the death of her husband:

1. If it is from the deceased's entitlements from his workplace, then it is an inheritance and is distributed among the heirs according to their prescribed legal shares.

2. If it is a grant, then it belongs to whomever the grantor specified:

If it was designated for the mother and she wishes to spend it on her children, she must be fair in giving to them.

And if she placed the money under the control of her son to spend on his siblings, he must be fair among them.

And if the grant was for the children of the deceased, it must be spent on them according to their shares specified by the granting entity, or equally if the shares were not specified.

There is no objection to demanding that the son, under whose control the money was placed, dispose of it with justice and wisdom.