I want to give my best friends brother a blowjob

I am a guy(21) and I'm gay. My best friend is a guy(21) and he's straight. We have been friends since elementary school and I have been sucking him off for two years now. His brother(22) is a year older than him, he has no idea I've been sucking his little brother off, and I've met him multiple times..hung out all three of us before. I am currently messaging his brother pretending I am a girl, and I want to tell him soon that I am his younger brothers best friend and ask him if he would be open for me to suck him. Without my best friend knowing, obviously. I understand this has the potential to ruin my friendship if he finds out but it also has the potential for me to help his brother get offTL;DR*I want to suck my friends brother off but I'm worried he will tell my friend and ruin my friendship with him.