At least for that time they lead and love the Sunday gathering, your MC should have the authority to make the calls they think need to be made… cut a song, do an extra prayer, cut and ad, change the song order mid-service, even tell the preacher they’ll need to rush through their talk (although I imagine something would have had to have gone seriously wrong for that – but the principle still holds).
See, if you’re going to hold them responsible for the meeting being an encouragement to those there, you need to give them the reigns. From 10mins before the meeting starts to the moment the meeting ends, for everything to do with the meeting, the MC should have the right to make the call he thinks is best. Even if the Pastor thinks its the wrong call at the time, that’s usually something that can be discussed later.