Wake up call about online predators

My older brother sent me an article about predators on Discord and I'm genuinely freaked out now. My 12yo is obsessed with gaming and uses Discord to talk to his squad. He says it's just his IRL friends but honestly how would I even know? I tried asking him about it directly and he got defensive. I don't want to be the paranoid parent but this stuff is real. How do you guys approach monitoring without making your kids feel like you don't trust them? What's the right balance?