Were you able to record replays between you and your friend? You may want to look back on the replays and reflect on what actions that you took in each match that he took advantage of. Are you being too predictable? What actions does he do that you can find an opportunity to punish them or at the very least predict in a given situation? These are some of the questions you should be asking yourself when reviewing each replay, or at the end of each match if you can't make replays for yourself.
If he's 2-stocking you over and over again, then it's a part of the experience of improving yourself in Smash Bros., or in any competitive-minded game really. Every player has to eventually be humbled by someone more experienced than him or her, and some, probably most, players go through this several times. It's what the loser does after the match--reflecting on the match, trying your best in the next one--that allows him or her to improve their skills and eventually go toe-to-toe with the winner.
As for your friend's attitude towards Olimar, I would say that those remarks are kind of expected for a generally defensive character. You shouldn't pay much attention to those.
If it's possible for you, posting replays between you and the Shiek/Samus player in the video thread can help you get critique on what you should exactly be improving on.