Do you think your brother has stepped over the line and become abusive?
There is inter sibling behaviour and there is a line where it becomes abuse. This is basically when the victim has little or no defence against them.
Denial is simply an avoidance strategy. He knows he is doing wrong, otherwise he would be saying something like - huh? was that wrong to do? It's another way of getting to behave how he likes and dodging the consequences. He has spotted you as an easy enough target.
I think you would be best telling him to modify his behaviour towards you or you will not see him again until he does. You do not have to tolerate this treatment.
That's your decision.
