Understanding is different than excusing a behavior...
So, what would you have done, KESSED? enlighten me...
and also explain to me how you solve something without working on it...
I guess "hitting" is something that I would take VERY seriously - and I wouldn't subject other people's children to my child is she was a know "hitter". And that's what you say your DS is. He could actually hurt an 18mo with the size difference.
Hitting isn't OK. It's not OK for a parent to hit their child. And it's not OK for a child to hit someone else.
So I would say to do whatever will work for him to STOP the behavior immediately.
I'm all for "working on" good manners, and helping out around the house. But hitting is serious. And it's not OK.