Everything was interesting to the young man

不行。
be interesting to sb\do sth或者be interesting that是固定搭配，对……来说是有趣的。
例句：It would be interesting to know what he really believed.
了解他的真实信仰是很有趣的

不能

be interesting to sb.对。，。。来说很有趣

可以这么改：
Everything for the young man was interesting.

不过就不是原意了。