165 seems a strange temp. Either one doesn't do any research at all like my brother and cooks it like a steak or prime rib - figuring its done around 125.
Or 2 minutes to google 'when is brisket done' to remove it at 190 or above.
So I figure your buddy must just the way it comes out at 165
Hell my wife piles cheddar cheese on my bolognese that I had simmering for 3hrs. Cant argue with 'that's the way I like it'.