Zakat must be paid by every free Muslim, man or woman, who has a nisab (the required amount of wealth). As for the insane and children who have a nisab, if their wealth is under disposal or in circulation, their guardians pay it on their behalf. If a person dies before paying it, it must be taken from the estate before paying off any debts, if there are any, and the heirs share the inheritance.
Senturk, Omer Faruk. “Charity in Islam” Tughra Books Press. January 2007