Working as a cantor, I've never been asked to do that, but in a few cases, it seemed necessary to prompt the priest, lest he skip an element of the rite. If a priest becomes consistently forgetful, it may be prudent to have him always celebrate Mass with the assistance of a deacon; of course, a knowledgeable adult server could help head off omissions as well.

You're up very late Chonak. Do you ever sleep? I'm just home from work.

What you're describing as a "prompter" is a bit odd, but it sounds like he just needs a good MC. In any case, it will be much less obtrusive than anyone else. Just like an MC would typically do, he'll just stand next to the priest, and point out the prayers for the priest to pray. This should solve his problem. If you have questions, feel free to PM. I've been MC more times than I can count, and also trained other men in our parish to do so.

That being said, I've never seen a priest so forgetful so as to omit the entire canon. Is he an elderly priest, or perhaps infirm in another way?

I have had to run through procedure and practice with a priest before mass. They seemed to appreciate being shown where resources were located and where and what books to follow, especially visiting priests.

Consistency is key. My priests know when they enter they will not have anything unexpected thrown at them. Predictability is good and makes everyone's life easier.

he told me to prompt him but he doesn't want anyone to know or notice

Unless I'm missing something, this seems impossible. But an MC, of course, could solve the problem....

Also, they may not have been used recently, but MCs have always been a standard role in the Roman Rite, so there's no reason not to use one, especially if there's a need.

I once had a boss who told me if the deacon delivering the homily at the Mass went over the 5 minute point that I was to start playing to "cut him off" - like it was an Academy Award speech that went too long. Thankfully at about the 4.5 minute point the deacon wrapped things up.

early stage memory loss

Ah, yes- one of my now growing list of Piaget Curve maladies. Likely explains the crying baby syndrome.

Priests "wing it".
Musicians prepare.

Where in the rubrics (GIRM or otherwise) is the role of MC mandated?

Where in the rubrics (GIRM or otherwise) is the role of MC mandated?

As usual, the GIRM is vauge (it basically says "if you want, you can have an MC."), so I always base my MCing on the role of the MC at the Missa Cantata in the Extraordinary Form.

He is mentioned in this pdf on the usccb website.

Yeah, I'm not sure why that sentence is even there..

Unless they're just trying to say that a televised Mass doesn't use an MC in the same way a reality show (host) does..?

Still random, though.

I was thinking primarily of the older form. I rarely serve as MC in the usus recentior. In the former case, he's definitely not in the physical location to remind him: he is behind and to the right of the celebrant. Second, he has way more to do at Solemn High Mass than does the priest, and there are three moving parts who have to move together.

It isn't about hierarchy, for sure. A lay MC would make no sense!

In the context of the revised missal, that would really depend on the deacons, the music. and the church. During the Triduum, there are times the deacon is not present, e.g. the retrieval of the cross and the Blessed Sacrament or otherwise unavailable, e.g. the prostration and the solemn intercessions. Someone has to coordinate the deacon and servers for the Gospel if you use candles and incense. This is especially true if there is chant or if it is a larger church; it would be awkward to stand at the ambo during the first jubilus of the Alleluia. Someone has to make sure the servers are at the chair when the bishop comes to take or receive the miter and crozier.

The Offertory and Canon are perhaps the one place the MC is utterly useless and the deacon the better and more natural help, being that at least one deacon will be at his right, if not the other at the missal (or alternating if in the traditional form). This is true in any parish context. Obviously, my own experience is in very traditional parishes, both at home and in my parish near the university. You also have much knowledge of the liturgy that most clergy of any rank lack, and you have much experience as a deacon....

I for one think there should be two deacons, four at most (if you have the ordinary or a cardinal celebrating)...it's so odd seeing vested deacons with nothing to do. I realize serving as MC isn't nothing, but it is so contrary to generations of practice to wear anything except cassock and surplice. In the older form, the priest isn't even allowed the cope except for serving as the assistant priest to the bishop and at the 1st three Solemn High Masses.

I don't see it as hiding his diaconal identity. He wouldn't do so when in choir dress...