My brother accusing me of killing my mom? Does that count? Calling all his friends and relatives when my mom's body is lying in front of us in the living room? How's that one?
Then there was the idiot at work who asked when a couple lost their only son, "So, how's the twosome doing?" I don't think anything is worse than that, even my stupid-ass brother's unconscionable comment. He is mentally deranged.