She has children who minors and they have money in the bank – does she have to pay zakaah on it?
Question

                I have four children who are orphans, and they are all minors. They have money invested in an Islamic bank, and in three months time a year will have passed. Does zakaah have to be paid on it? Can the payment be made from the profits?.
Praise be to Allah.The majority of scholars 
    are of the view that zakaah must be paid on the wealth of a minor, if it 
    reaches the minimum threshold (nisaab), when one year has passed. That has 
    been discussed in the answer to question no.
    75307. 
The nisaab is the 
    equivalent of 85 grams of gold or 595 grams of silver. The wealth of each 
    child should be examined separately, and if it reaches the nisaab then 
    zakaah is due on it, otherwise no zakaah is due. 
If the wealth has been 
    invested, as in the case asked about here, then zakaah is due on both the 
    capital and the profits, and must be paid at the end of every year at a rate 
    of one-quarter of one-tenth (2.5%). So if the capital is nine thousand 
    riyals and the profit is one thousand, zakaah must be paid on the total of 
    ten thousand, so 250 riyals must be paid. 
This amount (250 riyals, as 
    in the example), may be paid from the capital or from the profits, or from 
    any other wealth owned by the minor. 
And Allaah knows best.