The purpose of telling a child that they can do or be anything when they grow up is to not keep them limited. Persuading them to put up with toxic situations because “what if you won’t find anything better” also translates that they’re not deserving of better or worthy of finding something better.
Toxic situations will never equal happiness and all most parents want is to see their kid happy. Anyone who is stuck in a toxic environment or toxic relationship will be persuaded by the people who really love them to make a serious change. Once this child found himself unhappy, he realized toxic is not the way to go.