Ron helping Harry calm down after a panic attack because he thought his scar hurt when it was just a normal headache
Ron learning how to use the telephone properly so Harry could call him if he woke up in the middle of the night because of a nightmare
Ron quickly making a joke and changing the topic when a conversation became obviously uncomfortable for Harry.
Ron telling the reporters to piss off when they tried to crowd around Harry.
Ron actually being the best friend Harry could ever have asked for.