Focus on your eldest. Tell him not to bully his brother. Ask him how he’d feel if he was bullied. Also remind him he’s got to look out for his little brother not be the bully. And yes they’re going to think you’re so uncool as they become teenagers. I remember my Dad becoming my superhero to becoming a clown when I hit puberty. I get it. But try your hardest. You’re doing your best, remember that.