~snipped~
So you're trying to advice him to quit his teaching job and focus on trading. By quiting his teaching job he's giving up on the kids he used to teach to focus on himself. if you ask me I'll call that selfishness.
To be frank, there isn't anyone on planet earth who doesn't have that tint of selfishness running through them. However, what makes other selfishness conspicuous is the level it's taken to without a bit consideration for others. You talked about abandoning the kids, why shouldn't the teacher be told to concentrate on pursuing whatever ambition they want? Passion alone without money doesn't pay bills. The teacher has bills to pay. The kids have parents who obviously are pursuing their own ambition too. If what the teacher gets at the end of the month as salary is mere peanut, why shouldn't they take the step of faith in getting something better? My only concern for the teacher is they've to get a good handle on trading before quitting their teaching job. Otherwise, they're more likely to suffer hardship.
Life isn't about the money that we were able to make but the lifes we were able to impact while we were on earth because when you finally depart this world, it's the memories that stays with us and not the money you were able to gather while you were here.
Life is about two things – money and legacy. Nothing says one can't have both. While money is relevant to us while we're still on earth, legacy comes to play when when we're gone beyond the curtails (dead). So, have you now seen that life is majorly about money?