What does the expression 'justified for him his own idea' mean?

I am reading a novel, and I did not understand one of the sentences in it. Following are two lines from the novel. The narrator is talking about a guy called Paul and her father.

They were once caught in a three-week rainstorm, my father said if you could spend three weeks in a wet tent with a man without killing him or having him kill you then he was a good man. Paul justified for him his own idea of the simple life; but for Paul, the anachronism was imposed, he'd never chosen it.

I did not understand the last sentence - Paul justified for him his own idea of the simple life; but for Paul, the anachronism was imposed, he'd never chosen it.

Could someone explain it to me? From the context, I think that it means - 'My father liked Paul's simple life, but for Paul it wasn't an option'.

Here Paul is explaining why his idea of what a simple life means is justified.

Justify means to prove that something is right or reasonable.

It is usually used in terms of morality, for example you could shock someone by saying:

'Paul told his father that he would shoot Mr X in the head'

This would be murder, we all accept murder is morally wrong. However if we knew that Mr X was just about to do something extremely terrible like kill an entire bus full of children..

'after explaining the situation to his father, Paul justified for him why he would do such a thing'