8year old being mean to his little brother

[Numbsnet]

My 8 year old seems to lack some empathy. Maybe that's normal. He understands feelings and can articulate his own feelings well. He can be upset if others are mean to him. But.... he purposefully makes his 4 year old brother cry.
For instance, DS2 wanted to bring me something yesterday. I was upstairs and heard him wailing. DS1 had grabbed it off him and raced upstairs to give it to me. DS1 knew it would cause tears.
DS1 regularly pushes his out of the way, or grabs things away, almost for the enjoyment of it.

I've tried talking to him about how it makes DS2 feel. I've tried to explain how if he was in that position, it would make him feel bad. He seems to get it, but then repeats it.

Last night, I was really angry after he hurt him again. DS1 said "naughty gets stuck in my head and I can't help it".
So, an explanation of sorts but I don't know how to provide him with the tools to work around that and change his thinking.
We have punished him but it doesn't have any effect.
My questions are, is this sort of behavior fairly normal in a boy of 8? How can we get through to him that it's better to have a nice kind relationship with his brother than this? I would say 95% of their time together is negative. DS1 mimics him, won't let him watch his cartoons, bully's him basically. I'm afraid it's hurting DS2 emotionally and DS2 will start modelling that behavior with his friends.

Could you focus on rhe good things he does with his brother - even if they are rare - and let him know how proud you are and make a fuss of him. It might encourage that behaviour and change how he views his behaviour.

naughty gets stuck in my head and I can't help it

That's an interesting statement!

Have you had issues with sibling rivalry in the past? I'm wondering if 'naughty' is him actually trying to describe something far more emotionally complex, something that he doesn't know how to put into words (I know you say he expresses feeling well, but some are maybe still too complicated). To me, it almost sounds as though he's trying to validate himself/his place in the family.

Does he get much 1-2-1 time with you? Does he see his brother as being annoying or always getting his own way? Having some quality time where he can talk/moan/whinge without recrimination and just be heard may be helpful as well. He doesn't have to like his brother, but he needs to learn to be civil.

"Siblings without rivalry" and "How to talk so kids will listen and listen so kids will talk" are two books that may be useful.