Everything boils down to emotion and greed some people do not know how to control their emotion and they don't also know how to control their greed. When they are in for it, there is absolutely nothing you can say unless they exhaust all the money on them before they will listen to you.
There is nothing wrong with gambling if it is done like a fun and not when the gambler uses all he has to do bet a particular game and which eventually when the outcome does not favour the gambler he will loose everything and plunge into emotional damage.
I study gambling, and there is a certain trait among the stories of people addicted to the game: when they are deeply immersed in the game and in debt, they stop betting on certain specific matches that they understood at the beginning of their gambler's journey. For example, a dependent gambler at the beginning of the path can only bet on a few events in a football match. And then, when things get really bad, such people start betting on everything, assuring themselves that they understand everything a little bit.
But the chances are certainly less!
And such a person understands this... and he hates himself at the moments of such bets.