It's his first marathon, it's all trial and error...Depends on how his body reacts to carbs..Me, if I eat a bunch of carbs for 2 or 3 days, I feel like shit. I went and do all protein 7 to 10 days before a half or full marathon. Day before I carb load...morning of the run coffee, banana and a bagel. Have him try and get up at least 90 min before he has to be at the race to make sure the carbs exit his body before the run (if you know what I mean) Everyone is different. I know people that do carb load 2 days before and run great.
PLEASE TELL him to start stretching the day before and at least 30 MIN before the run. Also, tell him NOT to drink unless absolute necessary at the water stations along the run. If he don't have to stop to pee, it's better for his first marathon.
After the run, eat bananas..Stretch right after. I actually set my alarm in the middle of the night after a big run to walk and stretch for 10 minutes..Keeps the soreness down the next day.
I hope he enjoys the marathon. I wish him all the best but he will have an amazing sense of accomplishment once he crosses the finish line.
No big intense workouts before the big run. Short, little runs, a few miles is fine. But I'm hoping he has ran at least 15 miles in one shot before the race or his legs will really be sore