That's... That's really tough.
I doubt he got the full context of the conversation he overhead. I can't imagine how frustrating that must be to want to have a fair contest for a position, only to find the higherups are seemingly giving the other guy an handicap. I don't think it was fair for him to take it out on Subaru though. I'm glad Subaru stayed true to himself and his goals over a friendship that was turning south.
In the end, it think the other guy came to terms with it by himself, as demonstrated by him coming by for a meal.