What is the ruling on being present in a Christian school with those who harm the religion? Is this matter common in schools in general? And how can one hope for the betterment of a country where religion is insulted and it is met with silence?

Working in Christian schools is not free of assisting them in achieving their goals, and their danger has been previously highlighted. If, in addition to that, there is blasphemy and harm to the religion, then one must leave this school and seek employment in other schools free from such things. As for the vain talk that comes from some individuals in workplaces, a Muslim must rebuke the speaker in an appropriate manner. If he is unable to do so, then he should distance himself from them and avoid them as much as possible.