核心问题
Say what he will, he cannot make matters worse. 请讲讲 say 的用法和意义。
词典解答
say 在这里是现在虚拟式(be 型虚拟式) = Let him say。在这种习语里，表示让步意义。以现在虚拟式形式出现的动词总放在句首。例如，常见的习语 Come what may(不管发生什么事)，Be that as it may(无论如何)。你提问的句子的意思是：“不管他怎么说，他已把事情搞得再糟不过了。”类例：
-
Come what might, they were alone in the world with no one to help them. (Dickens) 不论发生什么事，他们在世界上都是孤独的，谁也不来帮助他们。
-
Later writers, say what you will of their genius, have rarely equalled the elaborate beauty of the ancients. 不管你对于他们的天才怎么说，后世作家很少能够与古代作家语言的精巧优美相媲美。
-
Be he friend or enemy, the law regards him as a criminal. 不管他是朋友,还是敌人,法律都把他看作是一个罪犯。
-
Well, say it were wrong, what then? 好吧,就算错了,那又怎么样呢?
(参见 be , come what may)