Many writers rely more heavily on pronouns than I’d suggest is useful. For me this sort of thing comes under the heading Remember that Writing Is Not Speaking. When we talk, we can usually make ourselves understood even amid a flood of vague “he”s and “she”s. On the page, too many pronouns are apt to be confounding. I’d strongly suggest to the point of insistence that you avoid referring to two people by the same pronoun over the course of a single sentence; to be frank, I’d suggest that you avoid it over the course of a single paragraph.
