Is zakat obligatory on money from the sale of an inherited house if a year passes before buying another house for the mother, and is the one-third bequeathed by the deceased to be deducted, and is it permissible to give to a indebted son from zakat to pay his debt to the heirs?

The heirs must first execute the will. Then, the legatee must pay zakat (definition) on the money if it reaches the nisab (definition) and a year has passed. Every heir must pay zakat on their share of the saved money if it reaches the nisab and a year has passed. The fact that the money is saved for buying a house does not exempt it from zakat. Zakat may be given to any of its eight categories, including giving it to a debtor brother or settling his debt without any conditions.