Regarding who does blessings, the General Introduction to Book of Blessings has:
“18 The ministry of blessing involves a particular exercise of the priesthood of Christ and, in keeping with the place, and office within the people of God belonging to each person, the exercise of this ministry is determined in the following manner:
a. It belongs to the ministry of the bishop to preside at celebrations that involve the entire diocesan community and that are carried out with special solemnity and with a large attendance of the faithful. The bishop, accordingly, may reserve certain celebrations to himself, particularly those celebrated with special solemnity. [Footnote 27: See Sacrosanctum Concilium, art. 79.]
b. It belongs to the ministry of a presbyter or priest , in keeping with the nature of his service to the people of God, to preside at those blessings especially that involve the community he is appointed to serve. Priests therefore may preside at the celebration of all the blessings in this book, unless a bishop is present as presider.
c. It belongs to the ministry of a deacon to preside at those blessings that are so indicated in place in this book, because, as the minister of the altar, of the word, and of charity, the deacon is the assistant of the bishop and the college of presbyters.
But whenever a priest is present, it is more fitting that the office of presiding be assigned to him and that the deacon assist by carrying out those functions proper to the diaconate.
d. An acolyte or a reader who by formal institution has this special office in the Church is rightly preferred over another layperson as the minister designated at the discretion of the local Ordinary to impart certain blessings.
Other laymen and laywomen , in virtue of the universal priesthood, a dignity they possess because of their baptism and confirmation, may celebrate certain blessings, as indicated in the respective orders of blessings, by use of the rites and formularies designated for a lay minister. Such laypersons exercise this ministry in virtue of their office (for example, parents on behalf of their children) or by reason of some special liturgical ministry or in fulfillment of a particular charge in the Church, as is the case in many places with religious or catechists appointed by decision of the local Ordinary, [Footnote 28: See Sacrosanctum Concilium, art. 79.] after ascertaining their proper pastoral formation and prudence in the apostolate.
But whenever a priest or a deacon is present, the office of presiding should be left to him.”
[Excerpt from the English translation of Book of Blessings © 1987, International Commission on English Corporation. All rights reserved.]
