One thing I do remember when DDs started school was that they would suddenly become much tougher and less "nice". I think it was becasue they were asserting themselves at school adjusting to other children around them. I think that at 4 your DGS is old enough to be reminded that his little brother needs to be treated kindly because he is younger and smaller and doesn't understand/can't do as much, and treats such as you have described with the riding are an excellent idea,but as for whether one can do much more? I suspect not. A friend and her 3 brothers used to say to their mother when they were told to stop fighting "Why? We're having fun!" My 2 little DGSs are 3 and 22 months and each much easier when apart, but happiest together. The little one can wind his brother up and cry when he doesn't get his own way and the older one has been seen to push his little brother. when they both want the same thing. This is always picked up on as in "Why is T crying, W? Well, he's crying because he wasn't being nice to me" Hmm , a stage missed out somewhere, I think. It always distresses us to see our children or grandchildren not playing happily together, fighting or falling out, but I fear it is totally human nature. As long as they love and support each other when they are older and can look out for ach other when we are no longer around, that is all we can ask for.
What were the first ever records that you bought and when?
Parents-in-Law. What do/did you call them?