Let’s wrap up the discussion on lay Communion ministers. First, a concession to the physical condition of the priest or deacon:
[158.] Indeed, the extraordinary minister of Holy Communion may administer Communion only when the Priest and Deacon are lacking, when the Priest is prevented by weakness or advanced age or some other genuine reason, or when the number of faithful coming to Communion is so great that the very celebration of Mass would be unduly prolonged. [Cf. Immensae Caritatis 1; Pontifical Commission for the Authentic Interpretation of the Code of Canon Law, Responsio ad propositum dubium, 1 June 1988: AAS 80 (1988) p. 1373; Ecclesiae de mysterio, Practical Provisions 8 § 2]This, however, is to be understood in such a way that a brief prolongation, considering the circumstances and culture of the place, is not at all a sufficient reason.
“Unduly” and “brief” are usually non-overlapping concepts. The parish pastor is nearly always the best judge of this. Do we train seminarians for commonsense, or select for them, or not?
[159.] It is never allowed for the extraordinary minister of Holy Communion to delegate anyone else to administer the Eucharist, as for example a parent or spouse or child of the sick person who is the communicant.
When it happens, this can be rather spur-of-the-moment for the Communion minister.
[160.] Let the diocesan Bishop give renewed consideration to the practice in recent years regarding this matter, and if circumstances call for it, let him correct it or define it more precisely. Where such extraordinary ministers are appointed in a widespread manner out of true necessity, the diocesan Bishop should issue special norms by which he determines the manner in which this function is to be carried out in accordance with the law, bearing in mind the tradition of the Church.
The involvement of bishops is certainly good. Pastors, however, are the ordinary ministers in the parish, and are best-placed to make informed, discerned, and adult judgment calls on parish procedures as well as the formation of proper attitudes where liturgical service is concerned.
N. 159 has happened at all my parishes: parents send a kid up to receive Communion and bring back an extra for the parents who remain in the pew. Needless to say, I ended that practice quickly.