Not only when they lose a lot of funds, but also when they win. They have the mindset of "I won a lot so it would be okay to bet a high amount of money" then after losing that money will lead to that scenario. Hoping that they could win back the money they lose but betting a huge amount of money would just cause them to lose more. Also they have the mindset of "high risk, high reward" but without consistency and limit to themselves cause them to use all of their funds. Always remember that having a winstreak doesn't mean you will not stick to your consistency.
They should change that mindset and quit right away before they lose control and end up placing another bet. They can expect to win big but also have to admit that it is not easy to get and they might lose all their money, especially if they intend to recover previous losses where it will be even more difficult. The pattern "high risk, high reward, but we need to be wise before deciding" is something that must be owned so that we realize that gambling is just entertainment and nothing more. Don't chase something from gambling but let it come alone while you just want to enjoy gambling.