Church documents give a preference for using men to lead Communion Services (CS).
Firstly they should be lead by a priest or deacon, if they are available.
The next preference is to use an instituted acolyte, another male only position. From the liturgical book, Holy Communion and the Worship of the Eucharist Outside of Mass, n. 17:
“17. It belongs first of all to the priest and the deacon to minister holy communion to the faithful who ask to receive it. … It also belongs to an acolyte who has been properly instituted to give communion as a special minister when the priest and deacon are absent … The local Ordinary may give other special ministers the faculty to give communion whenever it seems necessary for the pastoral benefit fo the faithful and no priest, deacon, or acolyte is available. [Footnote 8 See SCDS, Instr. Immensae caritatis, January 29, 1973, 1, nos. I and II]”
The footnoted document about EMHC (Extraordinary Ministers of Holy Communion, who used to be called “special ministers”) also has this, about the bishop being about to appoint EMHCs for when “no priest, deacon, or acolyte is available”.
This 1973 document also had: "IV. The fit person referred to in nos. I and II will be designated according to the order of this listing (which may be changed at the prudent discretion of the local Ordinary): reader, major seminarian, man religious, woman religious, catechist, one of the faithful – a man or a woman."
So again the male preference: “reader, major seminarian, man religious” all males.
So by having a women lead the communion service, the parish priest has only done the correct thing if he does not have a deacon, instituted acolyte, instituted lector, major seminarian and man religious available, as the appointed person to lead it. This is assuming that the local Ordinary (bishop) has not changed the designated listing.
(The 1973 Insturction Immensae caritatis is in the book
Documents on the Liturgy 1963-1979, Liturgical Press, Minnesota, 1982, ISBN 0-8146-1281-4, pages 650-654).