What should I do?

My younger brother repeatedly tells me to kill myself and I take that sensitively because I know people and know of people who hurt so bad and he's ignorant to it. I explain to him that if he says that to the wrong people it could end up badly and he just says "they're weak minded anyways" ignorantly. Today was the last straw and once he said it i put him into a headlock and told him to take it back. He didn't... Once I let him lose I felt bad and said sorry but I don't know if it means anything.