Dear D.,
Well, the person who has to change is the 2 1/2 year old, and he just hasn't felt any 'pain' yet - he hasn't gotten the message that he has to stop being so bossy. You need to really spend some time with him - This is the drill - I have done this and it works -
Really stay on alert to when the 2 1/2 year old begins his aggression - intervene, yes, but also remove him from the room or yard. Take him to his bedroom and tell him that he cannot be so mean to people - then he will cry and kick and scream, and you just have to endure it until he quits. You do not have to say much, just say that you will not allow him to be so bossy - or whatever words that he will understand. When he has quit crying, clean him up, have him help you straighten up the room if he has messed it up with kicking etc. Then take him to the bathroom, pee if he needs to, drink of water, and wash face with cool wash cloth. It is refreshing and he will need it too.
Take him out to play or lunch or whatever the family is doing now, - no, he doesn't need to apologize - they just don't understand that and really do not mean it so just don't spend your breath on it.
To play and normal life until he does it again and then IMMEDIATELY pick him up and take him to the bedroom. It will work. He is just too young to try to teach with a lot of words . Really, this will work, yes, the neighbors and your mother and mother in law and sisters and husband and so on will tell you that is mean. No, it is not. It is being respectful to the child's stage in life and his understanding level.
You and your family, especially the 7 year old will be lots happier in the hours, days, and months ahead if you perservere in this .
There you are. I did do it. C. N.