Writing tips: mixed ownership
Every sentence has an owner, that is the key noun or object, the subject of the sentence.
Bob was always late for school. – so the owner of the sentence is Bob.
Bob was always late for school, and today he waved at his friend. He waved back. – this is obvious, but not correct, because Bob is the owner of the sentence, and any use of ‘he’ should relate to Bob. In this case, it should have been His friend waved back – just to be clear.
A more simple example would be: Bill and Ted walked into the bar. He liked this bar. – who liked the bar, Bill or Ted?
Ownership stays with the object of the sentence till that ownership is passed over. This is a common fault with new writers, who use sentences and paragraphs mentioning many people, yet also use ‘him’ and ‘her’ wrongly, since it is not clear who the labels belong to.