From a reader…
Does one have to report a priest who knowingly gave communion to a protestant pastor?
In my parish we had an ecumenical rorate mass [An “ecumenical Mass”…?] during advent and the protestant pastor present (who also gave the homily) [lay people are not permitted to preach homilies at Mass] was given communion in public at the alter for everybody to see. [?!?] I seem to be the only one who cares. Do i have to speak to the priest about this or does this not seem rather out of place for a young lay womam to confront an elderly priest? So far he has been kind enough to allowe me to take communion on the tongue. [The priest doesn’t have the right/ability to “allow” you to receive on the tongue.] I don’t wish to loose that priviledge (i know it’s right but noone here cares about what Rome says).
Since this was all quite public, and it is in the past, I would write to directly to your local bishop. Save a copy of your letter and any responses.
The document Redemptionis Sacramentum says:
[184.] Any Catholic, whether Priest or Deacon or lay member of Christ’s faithful, has the right to lodge a complaint regarding a liturgical abuse to the diocesan Bishop or the competent Ordinary equivalent to him in law, or to the Apostolic See on account of the primacy of the Roman Pontiff. It is fitting, however, insofar as possible, that the report or complaint be submitted first to the diocesan Bishop. This is naturally to be done in truth and charity.
Keep in mind that, according to can. 844 in the 1983 Code of Canon Law for the Latin Church only the diocesan bishop can decide if a non-Catholic may be admitted to Communion and under what circumstances.
Can. 844 §3. Catholic ministers administer the sacraments of penance, Eucharist, and anointing of the sick licitly to members of Eastern Churches which do not have full communion with the Catholic Church if they seek such on their own accord and are properly disposed. This is also valid for members of other Churches which in the judgment of the Apostolic See are in the same condition in regard to the sacraments as these Eastern Churches. [This doesn’t seem to describe the Protestant minister.]
844 §4. If the danger of death is present or [if] if, in the judgment of the diocesan bishop or conference of bishops, some other grave necessity urges it, Catholic ministers administer these same sacraments licitly also to other Christians not having full communion with the Catholic Church, who  cannot approach a minister of their own community and  who seek such on their own accord, provided that  they manifest Catholic faith in respect to these sacraments and  are properly disposed.
Do NOT instruct the bishop about the law: he knows it already. Just give the facts of what happened without lots of comments. However, you might ask the bishop if he gave permission for Communion to be received and for the minister to preach.
That said, for your own knowledge…
The Code of Canon Law and the General Instruction of the Roman Missal are pretty clear that the homily is reserved only to a bishop, priest or deacon who have faculties to preach. A Protestant minister cannot give a homily.
The 1993 document Directory for the Application of Principles and Norms on Ecumenism from the Pontifical Council for Promoting Christian Unity says:
134. In the Catholic Eucharistic Liturgy, the homily which forms part of the liturgy itself is reserved to the priest or deacon, since it is the presentation of the mysteries of faith and the norms of Christian living in accordance with Catholic teaching and tradition.
Also, Redemptionis Sacramentum clarifies the abuse of lay-people giving a homily.
[64.] The homily, which is given in the course of the celebration of Holy Mass and is a part of the Liturgy itself,“should ordinarily be given by the Priest celebrant himself. He may entrust it to a concelebrating Priest or occasionally, according to circumstances, to a Deacon, but never to a layperson. In particular cases and for a just cause, the homily may even be given by a Bishop or a Priest who is present at the celebration but cannot concelebrate”.
[65.] It should be borne in mind that any previous norm that may have admitted non-ordained faithful to give the homily during the eucharistic celebration is to be considered abrogated by the norm of canon 767 §1. This practice is reprobated, so that it cannot be permitted to attain the force of custom.
[66.] The prohibition of the admission of laypersons to preach within the Mass applies also to seminarians, students of theological disciplines, and those who have assumed the function of those known as “pastoral assistants”; nor is there to be any exception for any other kind of layperson, or group, or community, or association.
Going on, say there is some sort of ecumenical “pulpit exchange”:
[74.] If the need arises for the gathered faithful to be given instruction or testimony by a layperson in a Church concerning the Christian life, it is altogether preferable that this be done outside Mass. Nevertheless, for serious reasons it is permissible that this type of instruction or testimony be given after the Priest has proclaimed the Prayer after Communion. This should not become a regular practice, however. Furthermore, these instructions and testimony should not be of such a nature that they could be confused with the homily, nor is it permissible to dispense with the homily on their account.
Non-Catholic ministers don’t get a pass. They are not to give the sermon at Mass. They are not to be given Communion at Mass.
The moderation queue is ON.