That's interesting. Can you point to a specific prohibition?
"Can you point to a specific prohibition?"
I'm afraid I don't have an Altar Missal of the old rite handy to consult the rubrics.
Obviously, non-celebrating priests can be called in to help with the distribution of Holy Communion at the old Mass, but I don't recall seeing anything about deacons, sub-deacons or acolytes being permitted to do this.
Perhaps someone reading the thread might have a copy of Fortescue which they can consult?
To be honest, even in the N.O. I always receive our Lord on the tongue and try to avoid handling the Sacrament as much as possible, so maybe I am being over-cautious in my assumptions.