Of the 2 boys, I think Andrew is the older/bigger boy. Look at the sweater the little boy is wearing under the vest.
Then look at Andrew’s sweater while he is listening to Mrs Hastings phone call.
Also, in the video Mrs D says kids your little sister and I think only the older boy kisses her. Then look at the shoe strings, the little boys are red (A is always tied to red right?). The older ones are blue. (Andrew, not A?). Just a theory! Also did anyone notice A’s ponytail?? Is it a girl? Could the younger boy have had gender issues and so they were sent away?? Just some thoughts!