I have two roosters with very heavy single combs and they're weighing down on their nares. I've thought about how they manage to breathe, but they both seem unhindered in their daily activities.
Recently, I had a hen with obstructed nares that couldn't breathe very well. She had a slight discharge that seemed to be an issue. I used terramycin ointment on her nares for a week, and it helped.
My take is that he's normal in every respect, good comb color, good level of energy, that I would not do anything drastic at this time. I don't believe he has a cardio problem or his comb color would be much duller.
If he becomes noticeably more inclined to open beak breathing, then comb dubbing might be considered. I've done partial comb dubbing on a hen once that had an overly large comb the others were always ripping off her scalp. It's not complicated surgery, you simply trim away the undesired tissue, cope with the profuse bleeding, and it heals in quick order.