My 4yo physically hurts his 2yo brother constantly. Is this normal?

They will be playing together nicely for a while, then out of nowhere, a switch flips and he decides he doesn’t want to share the toy anymore or wants the toy his brother has or even totally unprovoked, he will hit or scratch or push over his little brother. He has caused bruising and physical marks. This causes loud crying from our 2yo, who then will cry for a moment and seek hugs and reassurance from me or his dad before going right back to playing with our 4yo.

We have tried time outs, “breaks”, quiet time, taking away privileges, and none of it works. None of it. I have tried coaching him on how to calm himself down, to walk away when he feels the urge to hurt his brother, but he won’t. Structured activities only put a pause on the behavior until something about the game or activity creates friction between them.

It is exhausting, to say the least. We are tempted to let his little brother exact revenge on him but then it turns into a fight that needs to be broken up. I don’t want to start spanking him but it almost seems like the only thing we haven’t tried yet.

They have been home for 5 straight days, no daycare, no work for us, and we are completely burnt out. They will be home for two straight weeks coming up for Christmas and new years and we are dreading it. I will try to schedule some things to break up the monotony like play dates and family visits but the days at home will be long.

Can we expect him to grow out of this or do we get to enjoy this for the foreseeable future?