I'm not really a body builder, but I ha s done my fair Share of bulking. I would follow your brothers 5-day split I know many bodybuilders swear by this. I also agree with the 4500-5000 calories a day. I usually do a dirty bulk and eat everything, but you can choose. I would also like to say congratulations on being sober, I'm glad you have found a hobby that you can do to better yourself. I have also found that lifting in its own way is like therapy for free.