Is what the young man did correct, leaving his job at a company that produces musical discs and films, and where there is mixing of sexes, out of fear of sin?

It is not permissible to maintain the machines of a company that predominantly produces forbidden films and songs, as this constitutes cooperation in sin and aggression. Allah, the Exalted, said: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty."