Is it permissible for a woman to dispose of her deceased husband's wealth, and do the children have the right to claim it?

If the money was deducted from the father's salary, then it is to be distributed among the heirs according to their prescribed shares in the Book of Allah, and the son has the right to claim his share.

However, if the money was a grant from a certain entity, then its distribution is up to the granting entity. If the son is among those who meet the conditions, then he has the right to claim it.

If the money is from the father's estate and has not been distributed, then the son has the right to claim his share after proving it. If the money belongs specifically to the mother, then she must be fair among her children in giving, and the son has the right to demand fairness from her.

The son is advised to fear Allah, be dutiful to his mother, and treat her kindly.