这句话的意思更可能是“看起来他对发生什么事毫/漠不关心”be/seem detached“（态度上）超然的，与己无关的”。seem这里没有主动表被动，就是简单得系动词，detached是ed分词充当表语。
如《科林斯英汉高阶双解学习词典》的解释与例子：
1. ADJ-GRADED超然的;冷漠的;不带感情的 Someone who is detached is not personally involved in something or has no emotional interest in it.
He tries to remain emotionally detached from the prisoners, but fails...他试图不带感情地对待那些犯人，但是做不到。
It is written in a detached, precise style.行文冷静客观，一针见血。