Is it permissible to pray behind the Imam of the Grand Mosque via television during a curfew on Friday, and what should the congregation do if there is no one among them qualified to deliver the sermon?

The Friday prayer, as described, is not valid due to the absence of some conditions for following the Imam, such as the disunity of place between the Imam and the worshiper. Since there is no one to deliver the Friday sermon and it is not possible to go out to perform it in the mosques, there is no sin upon you if you pray it as Dhuhr.