Is it permissible to demand that the orphaned son repay his procrastinating father's debt? Am I entitled to take the money if the father refers me to his son? Would that be considered an encroachment upon the orphan's property?

No one has the right to demand that the sons of the debtor pay their father's debt from their own money, unless they guaranteed the debt for him, or the father had a settled debt upon his son and the creditor transferred the debt to him. The scholars have stipulated that the son is not obligated to pay his father's debt.