ANSWER:

If you trust that he will give from his own money the equivalent of your zakat and that he is not lying, this is permissible as it is a gift from his side. 

However, you must calculate what is saved in your cupboard and give the zakat on it personally just to be safe as given more as he claims doesn’t cover it as he doesn’t know how much you have. 

QUESTION: My dad manages my zakah and my bank. I informed him i have lots of money in my cupboard since many years. He told me that’s ok because he pays extra zakah every year so it gets covered in that. Is it ok? I am confused because of the niyah aspect of it.