Dear Laura,
You need to go to the library and find a good book on two year olds. It will quiet your fears somewhat and help you understand what these guys 'are thinking' or 'are learning'.
Also study a chapter or two on young children's play - at first they play alone, then side by side without enteracting, then they play cooperatively - but between all of those stages and the more stages to come - they try to learn what to do and what not to do and what the outside society will allow them to do.
Once I saw my beloved 2 1/2 year old gr grand daughter come along side a child who was only slightly younger than she was. She just took the doll buggy away from him and said "I need that!" She whisked it away and he went on his way . I didn't mess with them, but I was quite shocked to see her so haughty and unkind to a friend.
I think that is an illustration about how this age person can be. They just don't know what is right or wrong. Probably your son has started to catch on within your own household that there are societal rules - but he doesn't understand how to handle bullies. If a toy is in dispute, then just take it away from both, is a good plan and doesn't cause warfare between mommies. The kids don't need to be told what happened right then, just take them both by the hand and find something else for them to do. They will get the picture sooner or later, and your son will feel supported and secure.
I used to have a German Shepherd dog named Tony when I was a little girl. My mother told me that Tony would not let me go into the street, he would just get close to me and sort of bump me back into the yard. That is what I mean about your handling the children right now, at their age.
Actually, I think that you son is far ahead of the other one. He is already showing that he has a brain working up there and that brain knows that something wrong happened, he just doesn't know how to handle it. You can bump him into the safer situation for a while and he will catch on right away, I bet you $10., and that is the highest bet that I ever make.
C. N.