是什么使他变成了(现在的/这样的）他?
后面应该是问号.
那么此时就会是个疑问句,正常的会应该是It is what that he makes him what he is.但现在是强调句的疑问句：What is it that he makes him what he is
后面的what he is 是 宾语补足语.你看看,he makes him what he is.你在him后面加个be动词,这是成立的：he is what he is.