There is no way I am going to believe that $28 spent on a single bet was going all in with a left over, except like you said, the player is a high roller which means that he or she might have been spending a much higher amount on each of the spins on this game.

But that is absolutely not important anyway, what's important now is that he won and the amount is crazy, one that is capable of changing a poor man's life and turning him into a millionaire in local currency.
A big congratulations to whoever this winner is, but this is if he or she is not a high roller as we speculate because if he or she is, then maybe this amount means nothing.