I don't know if we could say our playing is on a competitive level, but he did definitely get better over the years. We used to only be able to play a couple matches before he would give up on me, but now we can play for ages and stay pretty much even. :P
That sounds about how my little brother was too. Except these days he'd crush me in Smash Brothers. He actually learned how to play it competitively, while I play it as a button masher most days. But button mashing is fun!