Errr eating lots of little meals is actually a method that people use to LOSE weight, it doesn't work but yeah it's definitely not a weight gain plan. The only reason it would work is because it's easier to eat more that way, but he's already said he eats lots so it's not like he's thin as a result of starving.
That said, as far as I recall you're like 8 feet tall or something so all that RDA nonsense needs to be upped a bit anyway just to attribute for that - eating the same amount as is recommended for someone of my size isn't gonna do the trick for you