What is the ruling of Islamic law regarding preventing drivers working in households from praying in mosques and compelling them to pray at home, while not allowing them to go out unless accompanied by members of the household?

Employers must enable their workers to perform congregational prayers, in order to cooperate in righteousness and piety. It is not permissible to prevent them, because it is a religious obligation, and obedience to Allah and His Messenger takes precedence. If a worker is prevented and finds no alternative, he is excused.