What is the ruling on a man bequeathing a sum of money for the soul of his mother, while he has two married daughters?

If the bequeathed amount does not exceed one-third of the deceased's estate, the heirs are obligated to disburse it as charity. However, if the bequeathed amount exceeds one-third of the estate, only up to one-third of it is to be disbursed, and any excess depends on the consent of the heirs.