What is the method for determining the date of Zakat payment for the past year when it is not remembered, and how is it paid according to the Gregorian calendar? Is it permissible to give Zakat to young siblings who live with their father? Is it permissible to give it to relatives in the form of gifts to avoid embarrassment?

If you are not certain of the exact time when Zakat becomes due, you must pay it at a time when you predominantly believe it coincides with the due date or before it. The Zakat year should be calculated according to the Hijri calendar, not the Gregorian. It is permissible to give Zakat to younger siblings if they are in need and their father is unable to provide for them. However, if the father is well-off, it is not permissible. It is permissible to give Zakat to relatives in the form of gifts without informing them that it is Zakat, provided that this does not result in discontinuing previous gifts you used to give them.