Man up he did already when he built the aforementioned tech company, didn't he? And while his kids don't have cancer he himself might get one having the stress he has. Or didn't the tweet author get some himself to understand?
Being not a soldier, fire fighter or police officer doesn't mean being out of the - actual - harm's way. Here we talk not about the ego - primarily - but about something bigger than that. Elon uniquely helps in elevating important topics to the conversation level. Fall of his ability to maintain financial independence while pulling state of the art in tech ahead will, no doubts, add to arguments of skeptics and naysayers and may have a chilling effect on certain approaches to handle modern problems, be it AI, climate change or retractions of democracies.
I'm not sure the tweet author really understands what he's talking about.