It's possible to win poker with a weak mind, but it's much harder. Poker requires mental skills such as attention, concentration, strategic reasoning and the ability to control emotions. If someone has a weak mind, they may struggle to maintain their focus and concentration for long periods of time, which can affect their ability to make well-informed decisions.
Plus, poker can be emotionally challenging. Players must be able to handle the pressure and stress of high stakes, bad streaks and the emotions of other players at the table. If someone has a weak mind, they may be more susceptible to the influence of emotions, which can affect their decision-making and their ability to keep their game under control.
That said, mental strength isn't the only factor that determines whether someone can win at poker. Other factors such as skill in the game, strategy, experience and luck also play an important role.