If there is regret when playing and lossing on gambling, then it is obvious that the player had lost more than he can afford to loose. It is possible that due to the heat of the moment, he was triggered chasing losses to recover his losses but instead of recovering the lost money, he ends up losing more. If that often happen, then the gambler need to reflect on his action. I agree that the gambler should slowly take a break on gambling because it is not normal to regret the gambling activities and then at the end of the day the gambler still continues to gamble non-stop.
And the gambler can take this moment of regret more seriously, namely by reducing his gambling activities to reduce the number of losses as well. If he starts to learn not to get emotional in chasing his losses and can think that it is a risk that he has to accept, he can start to reduce his gambling activities so that he does not experience as many losses as before. By reflecting on what has happened to him at gambling, he can see the impact gambling has had on him and will make changes so he doesn't get too deep into gambling.
I agree, after all the decision is on the gambler. If he really wanted to quit, there is nothing to stop him doing it. It is the matter of how strong his will on executing his decision of quitting.
The decision will rest with the gambler and he should consider it before deciding. If his will is strong, he can stop gambling or reduce his activity in gambling.