Is it permissible to give the zakat for missed days of Ramadan to my poor brother, and what is its amount?

The sister who asked the question must make up for the fasting days she missed. If the delay in making up the fast was without a valid excuse, then along with making up the fast, she must also pay an expiation for the delay. This expiation is feeding one poor person for each day she missed. Its estimated amount is one mudd of the staple food of the country, which is approximately 750 grams. There is no harm in giving the expiation to her brother and his children if they are poor.