Is a person sinful if he does not forbid evil and does not leave a gathering where religion is mocked, such as the hijab and death, despite his dislike for that?

Mocking others is either mocking individuals, which is a major sin, or mocking the religion, which is disbelief that expels one from the faith. It is not permissible for a Muslim to participate with those who mock, or to condone their actions, or to remain silent when they are able to change it. Rather, they must distance themselves from them, "Indeed, you would then be like them." If you are unable to change it with your hand or tongue, then do so with your heart, meaning hating their action and leaving their gathering if possible. A distinction must be made between places that can be left and those that cannot, such as colleagues at work or study that cannot be dispensed with. In this case, a Muslim is excused if they are unable to leave the place or are harmed by doing so, but they must show their disapproval and try to stop the wrongdoing.