From a reader…
Can a deacon serve as acolyte in the Extraordinary Form Mass?
Sure. If there are not enough servers for the sake of a Solemn Mass, and for some reason you have a plethora of deacons and a paucity of non-clerics, sure. It’s a little hard to imagine the scenario, but, sure. A gathering of priests and deacons somewhere? Perhaps some of the boys couldn’t show up so you have to fill in?
While it is better for a deacon to be deacon or subdeacon, he can serve if need be.
As a matter of fact, it is a good thing for priests and deacons – let’s not exclude bishops – to serve Mass once in a while. I once had a cardinal serve Mass for me. That’s humbling. I have served Mass for visiting priest friends. It’s great!
It’s okay for a priest not to concelebrate, but to sit in choir in proper choir dress. It’s okay for a priest or a deacon to take a serving role. I will often act as a deacon on Sundays so we can have a Solemn Mass, which should be the target for Sunday worship.
It’s okay for us to get down off our high horses and pick up the curry comb.