Yeah, it's the best solution for him to re-assess whatever mistake he made during that failed session, instead of pushing his way to keep playing and most of the time the outcome will be against him, you need to be wise to keep that emotion and treatment towards your gambling participation, having that kind of understanding will let you to keep yourself in shape.
By introspecting ourselves on the mistakes we have made before, this will certainly motivate us to be more careful in every decision and action we take in the future. For wise and responsible gamblers, have good thinking because opportunity does not come a second time and this can be applied in gambling so that we remain consistent in maintaining good control.
Wise and responsible gamblers don't let themselves reach a point where they make mistakes that they wouldn't want to repeat, it barely happens that a responsible and wise gambler would lose all their money and don't stop gambling at the right time because a wise person would think twice before taking the next step so that they don't have to face severe negative consequences of their actions and they can steer clear from any sort of situation.
So such gamblers would always stay in control no matter what happens. They will have their budget and time fixed and they won't cross the limits they have set up for themselves in any situation, they have enough self-control to be able to control the urge to gamble.