I see your well-intentioned encouragement, though in likelihood, his doing-well colleagues could also be investing in a disciplined manner. Other things being equal, the wealth gap continues to grow. This is how the rich gets richer and maintains their place in the pyramid.
That’s why revhappy’s advice is well worth following — don’t compare cos there’s no end to it.
Still, I think some healthy comparison may be good to push one self harder, esp. if you are still early to mid career. For the typical person in their late 40s and 50s, it can be a quite hard for them to push themselves further unless they are willing to make some sacrifices and lifestyle adjustments. That’s why for this group, they often console themselves by telling themselves not to compare!