My younger brother (by 4 years) and I would get into fights when my parents were out for the evening. Not horrible, but maybe a punch here or there. I stopped when he got taller than me...
I don't have an answer but I think your solution sounds most helpful.
They get along famously because... DD is the boss mare. DS is just along for the ride.
However, he just figured out how to retaliate. He clocked her the other day, and yesterday he bit her foot. Is it bad that I laughed and cheered him on?? Only because he has been her minion for a good 6 months now and taken SO much abuse!
But I hear you on the earplugs, for sure!!
We couldn't all be cowboys, so some of us are clowns.
Yeah, my older son is definitely boss mare (erm, so to speak), but younger recently learned that WAAHHH! makes us come running and assume Big Bro was up to no good. Now, we're on to them both. Half the time it's Big Bro harassing Little Bro, and half the time it's Little Bro lamenting that Big Bro won't let him have his way (when it shouldn't be had).
Flash Gordon, like you're seeing, around 18mos the hitting started. We too were glad he could fight back--and most of the time, the boys get along great. Heck, today, it was practically all Younger causing the drama and the headaches. But Elder didn't help. (WAAAHHH! gets SO OLD SO FAST.)
One is in bed, one will soon be in bed. Now, if only they'll sleep...
I have three older brothers, and we are all spaced strangely. The oldest is about a decade older than the middle two (he is only my half brother) and the youngest of the middle two is a decade older than me (they're both my full brothers). The middle two have always been trying to be only children! There are a few precarious stories from their childhood : one almost got pushed down the stairs, tiny fights. My aunts favorite story is from a vacation when bro #3 came crying to my mom and said "bro #2 said he will always be older than me!"
Boys will be boys
We would leave them at home while we went on vacation and they were in college and almost always there would be a call from the oldest brother "well so and so called and so and so did this so I had to go over there"
They still have a little rivalry that peaked more or less in their mid twenties when they didn't speak for a few years, now they sort of get along, bro #3 has embraced his middlechildhood (plus he's the smartest) bro #2 still wants to be an only child but now he's taken to stealing the spotlight from me. It's okay though I'm the only girl so doesn't have anything on me .
All kids will be different, I was always fine with my brother making the spotlight about them - a little less talking about me made life easier!