Don't think you need expert advice on this manner, just a little common sense. The first choice (in my view) was correct from Meso_z, three times a week full body. And keep the full body thing going for a good 6 months. Keeping it short and simple compound exercises mostly. Squats, benches, rows, etc. With a max of 6 exercises at 3X8-12 reps. If he does have great genetics, than progress will certainly advance at a steady pace. You want your bro is adapt to working and to a point where he looks forward to the next workout. So three times a week may be a good start.
The common thread lately in BB'ing training seems to be slipping back to the basic style of training, as full body workouts, 2 to 3 times a week (BB'ing falls into phases, or even fads, that people seem to change to over time). If your bro decides to follow Splits after the breaking in period of 6 months, than alternate between a push/pull style of training on workout days. There are dozens of splits, some rather stupid in my view only.
Of course I would have to ask the question, is it the bros idea to workout or was it yours for him to start lifting? He may have the genetics, but the interest and desire is another thing all together. Plus the free time factor, which can be handled very well by short, to the point full body workouts three times a week. Good Luck.