Hi Rose
I have a younger brother who sounds a lot like yours.
He used LOVE to make threats and hurtful remarks so he could then talk down to me and belittle me to make himself feel good.
I think your best bet is to do what Ronda said, ignore him and don't feed his need to be critical or mean. That's what he wants.
I did that with mine. But, I also told him what I thought of the person he'd turned into too. I said all that I needed to say in a very calm, CONFIDENT voice, then left. That was the first time I had ever stood up to someone who I used to fear on that level. I found out that I was stronger than he was that day.
If telling your brother what you really think of his attitude isn't an option, find ways to show him your done with his negative ways. If it's possible when he starts acting or speaking in a way that makes you anxious, pick up a book or your cell. Turn on the tv or the radio. Make it obvious that your simply not gonna do the usual routine with him anymore. And if he gets mad, so be it. He can be mad.
Eventually he'll see that your his sister, and not a whipping post for his frustrations.
Missy