Aren't we all great??
Your friend is not a great player.
He might know odds
, but he's expecting to win just because he leads at some point in the hand. The average winning hold 'em hand is two pair, and he doesn't even beat that. He may be over committing himself in trying to be "aggressive" against opponents who do not understand aggression. If you are playing against calling stations who won't fold, YOU are the bad player if you refuse to recognize and adjust to the opponent's tendencies. Don't curse them for being who they are.
TPTK is good but not great. The best hands also have good drawing potential, such as to a flush or straight. If your friend completes such a hand against a calling fish, THEN your friend should put the big money in. Especially if the fish hits two pair - your friend should stack him. But don't try to get too much out of a middling hand.
Furthermore, the opponent here was about a 7:1 dog. Be happy that he called! The fact that he sucks out is really a minor point, and needs to be expected once in awhile. We need to savor our suckouts because they reward bad calls and keep them coming. Your friend appears to be results-oriented, and focused on short term results at that. Good players are beyond that.
Sounds like he tilts and blames others or blames the fates when he loses.
Poker is ZEN-like when it comes to killing the ego and dispassionately examining self. You can't play with wounded pride and a sense of injustice and expect to see your own strengths and weaknesses.
Your friend is not a great player. He over-reacts to normal statistical outcome and variance, he has a short term view of the game, he does not adjust to and exploit opponent tendencies and he is not doing the work of honestly and comprehensively deconstructing his game.
He's really in an early stage of poker development. He's playing only his cards.