The ruling on the zakah of money accumulated for a child

Question:
The questioner says: My mother passed away, and she left behind money that belongs to my younger brother. She had been setting it aside for him from his salary, which was my father’s salary (may Allah have mercy on him). She did not know about paying the zakah on the money. He says: My mother passed away and left behind money that belongs to my younger brother, as she had been accumulating it for him from his salary, which was my father’s salary (may Allah have mercy on him). She did not know about paying the zakah on the money, and she passed away without having paid the zakah for all these years, even though the amount of money was not large. What is the ruling?

Answer:
Is what she accumulated from the child’s share? Or did she accumulate everything that was paid to the father for this child, while he has other heirs? It requires a detailed explanation. However, in any case, if this accumulated amount is what this child is entitled to, and several years have passed during which it reached the nisab (minimum threshold for zakah), then zakah is obligatory on it. One-quarter of one-tenth is to be paid for each past year. His guardian and the one looking after his affairs should pay it.