I like to think that the dynamic between Dr Rieux and the other doctors in Oran mirrors that of Albert Camus himself and the other French intellectuals of the time, with Dr Richard serving as his equivalent of Jean-Paul Sartre...
I don't think it'd be a stretch to assume that most of the other doctors presented at the health commission were more well-off in terms of their lives, as Rieux becoming a doctor despite his working-class background (and also perhaps implied to be beloved by those who are less fortunate in Oran due to his kind-hearted nature) is presented as a more personal case of perseverance. With the doctors being quite hesitant to accept Rieux's ideas despite all of his evidence, it sort of reminds me of Camus himself, having lived a childhood in a much poorer environment in French Algeria than his companions in France, with him feeling as if he never quite fitted in with Sartre's circle despite their closeness.
There is little revealed about Richard in the book (and he is only really important in his role in Part 1), but its made clear than in a time of confusion, he was one of the first people who Rieux turned to in a time of confusion out of all of the leading doctors, implying that they may have been on good terms beforehand. It's the differing opinions on the nature of the sickness, however, that leads to them beginning to disagree. It isn't as dramatic as the falling out between Camus and Sartre, but one thing made very clear is that during the commission, Richard keeps trying to play down Rieux's words despite the latter's increasing agitation and anxiety (and Rieux's anxiety does play up throughout the book, especially in that first part). Like Camus himself, Rieux was going against the words of his counterparts without fear, unafraid to make his own decisions and express his concerns (such as on the acts of the Soviets), which led Sartre and many others to argue against his words and cease their friendships with him - more specifically, one of the triggers of the falling out being Sartre defending the Soviet camps, believing the actions of the Soviets to be for the greater good.
Something quite out of character is how Rieux doesn't speak much about Richard's death, quickly passing over it - perhaps with the idea that their dynamic was originally much more closer than the book than shown, such a falling out had deeply affected Rieux. Although it is evident he believes that the other doctors did not do enough to prevent the plague from spreading in the first place, he still tries to pay Richard some respect in his work. As the narrator, Rieux wishes to only to report what he finds relevant, and perhaps his falling out with Richard was something he had rather forgotten about than dwell upon due to it involving his own personal feelings.
Of course, Camus and Sartre's falling out happened years after The Plague was written, but I thought it was an interesting parallel and that Rieux's beliefs (as the protagonist/narrator) may have served to show an earlier perspective of Camus' criticisms of his peers (+ I do sincerely apologize if I have made any misunderstandings of the text and of the figures mentioned in this analysis, or if it is not clear enough!!) ꒰ ྀི◞ ◟ ꒱
