I don’t have live access to current news right now. Based on the latest results I can recall, Jannik Sinner’s brother is Marc Sinner, who has been mentioned in several articles as a supportive presence at events like the Australian Open and other tournaments, though he’s not typically in the public spotlight. If you’d like, I can summarize what’s known about their relationship and Marc’s public appearances from recent reported coverage. Would you like a concise timeline of notable mentions?
For the most up-to-date news, you may want to check reputable sports outlets or the official ATP/Tennis channels. If you can share a preferred source, I can tailor a brief summary from that.