It’s necessary for authors to be careful and explicit regarding the use of pronouns when more than one person is present in the context of a discussion. The antecedents of pronouns may be perfectly clear in the writer’s mind, but to a reader it may be anything but.
Consider the following sentence, which seems to make perfect sense:
He told him that he would pick up his kids and take them to his house.
But there is a big problem if the author is thinking:
John told Jake that Jack would pick up Jim’s kids and take them to Joe’s house.
There is nothing wrong with using proper nouns when pronouns would result in confusion.