Sorry dude but silver/bronze in Season 4 is nothing like silver/bronze in season 1/2 for example. Most people who are no longer low elo don't understand how cancerous the game has become, and why simply learning to 'carry' games is alot harder than it sounds. And no, there is no skill difference not sure what your point was there

and yes playing 500 games will improve his skill and knowledge of the game. You can't argue that, because if he starts to win a majority of those games his MMR will rise so that he starts playing with ranked players higher than silver/bronze and gets a taste of playing against someone mechanically superior.
Im sorry about how can you argue that practice doesn't make perfect? Not like I'd expect him to wait 500 games but the difference between 400 and 500 games is like 50 hours gameplay.
edit: Also, having climbed from the depths of Bronze 5 myself I know how hard it is. When you are down there with the people who attack eachother verbally to the point where they are trying to feed hard to end the game when surrender attempts fail. You don't want to put yourself down there, and struggle to climb even more than necessary and those 100 normal games of practice will be the difference between you being able to carry the imbeciles or instead joining their ranks.