My Father's Work in the Police

Not totally incorrect but I think most people would say "I work as a policemen" "My father's work as a policeman". It sounds a bit less natural than "He works in the police" for example, "He is a policeman" "His work as a policeman was difficult"

My father worked in the police force for 30 years and retired in his early 50s in the rank of a sergeant.

worked in the police force OR worked as a policeman (but you will still be understood if you say "in the police")

I don’t think he liked his job very much, and I never heard him telling good things about it.

between two sentences that can stand on their own (they are correct sentences by themselves), you need to put a comma if you have a conjunction such as "and", "but"

He is a gentle, soft and agreeable man who doesn't like getting into a fight or even argueing with someone.

His main passion is to play the guitar and signg to entertain people.

I think he should have become a musician or a performer, but he chose theo become a police officer profession to earn a living for our family.

OR he chose the police profession (less natural) OR he chose to become a policeman

same thing again with the comma rule. the two sentences are okay on their own, so it needs a comma with "but" or "and"

My father worked in the police for 30 years and retired in his early 50s in the rank of a sergeant.

You could say "at the rank of sergeant" or "as a sergeant" to sound a bit more natural.

I don’t think he liked his job very much and I never heard him tellingsay good things about it.

He isn’t athe kind of person that people think of as a police officer.

He is a gentle, soft and agreeable man who doesn't like getting into a fight or even argue with someone.

His main passion is to play the guitar and signg to entertain people.