When should I exchange nouns to pronouns?Is there a obvious rule in it? 父亲今年65岁了,他以前是一名律师。父亲的爱好是旅行，经常去旅行。

This sentence is strange to me.

First, 父亲

Second,他

Third,父亲

I often hear that the English speakers avoid the duplications of noun.
Is it also in Chinese?

父亲的爱好是旅行 →　他的爱好是旅行 ( I thought it was right.)

I refer to a textbook and this is a solution for the quiz.
What is the purpose of this expression?

Why  dare the author to use 父亲 again?

I solved the quiz , often wrote "他的爱好是旅行" , checked the answer and it was not right. 

When should I exchange nouns to pronouns?Is there obvious rules in it?
There is no rules, but Chinese is also try to avoid duplication

父亲今年65岁了,他以前是一名律师。他的爱好是旅行，所以他经常去旅行. is totally OK.

Sometimes you can't, then try to avoid continuous duplication.

父亲今年65岁了,他以前是一名律师。父亲的爱好是旅行，所以他经常去旅行.

Author prefer synonym to eliminate duplication.

父亲今年65岁了,他以前是一名律师。老爷子的爱好是旅行，所以他老人家经常去旅行.