Your demand is pointless, they aren't going to bend a system just for one player.
There's nothing you can do about a ragequit after the fact, you can only prevent it from happening by preventing the situation that led to the ragequit.
If they leave after being ganked, maybe you should try preventing the entire situation by warding and pinging danger when a gank is coming.
Not saying it's your fault that they ragequit, just that Riot's not going to change things, so if you want to prevent the situation you should do something smart about it.