Well the Congregation for the Doctrine of the Faith begs to differ from Fr Kennedy: Responsa ad Proposita Dubia de validitate baptismatis 1 Feb 2008. The original is in Latin; here is the official English translation:
QUESTIONSThe problem with these formulas is not only that they are contrary to the law of the Church but that they are also contrary to the nature of the sacrament instituted by Christ. He instructed the apostles "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit" (Matt 28.19) thus specifying (in a manner Fr Kennedy considers exclusive and patriarchal) the three persons of the Trinity.
First question: Whether the Baptism conferred with the formulas «I baptize you in the name of the Creator, and of the Redeemer, and of the Sanctifier» and «I baptize you in the name of the Creator, and of the Liberator, and of the Sustainer» is valid?
Second question: Whether the persons baptized with those formulas have to be baptized in forma absoluta?
To the first question: Negative.
To the second question: Affirmative.
The Supreme Pontiff Benedict XVI, at the Audience granted to the undersigned Cardinal Prefect of the Congregation for the Doctrine of the Faith, approved these Responses, adopted in the Ordinary Session of the Congregation, and ordered their publication.
Rome, from the Offices of the Congregation for the Doctrine of the Faith, February 1, 2008.
Formulas using terms such as creator, liberator and sustainer do not specify the persons of the Trinity. The works of the God ad extra are works of the Trinity. Thus it is the Trinity that creates, liberates and sustains – albeit we may attribute “missions” to each of the persons of the Trinity, speaking of the Father as creator, for example. But we can also quite properly call the Holy Spirit "Creator" as we do when we sing Veni Creator Spiritus.
I have used this case as an example in my course on Sacramental Theology when looking at the form of the sacrament of Baptism. (I have just added a new footnote to my class notes.) As an aside, I always mention the grave consequences of such foolishness. Fr Kennedy had been at Brisbane for 24 years and the parish had 100 baptisms a year. Apparently, he and the curate alternated between the valid form and their own invalid form. So there were, say, ten to twelve thousand invalid baptisms.
None of those people can receive any of the other sacraments validly. If Archbishop Bathersby visited the parish to administer Confirmation, the confirmations would not have been valid for any of the people who were invalidly baptised.
It gets worse when we consider the case of someone who was invalidly baptised marrying a non-Catholic in a civil ceremony. Normally, if a Catholic marries in a civil ceremony without any dispensation, the marriage is invalid and a nullity can be granted by a relatively simple documentary process because of "defect of form". If, on the other hand, two non-Catholics marry in a civil ceremony, it is presumed to be valid.
So if it turns out that the "Catholic" was not actually baptised at all, the marriage, like other marriages of two non-Catholics, is, in fact, valid after all. And any subsequent marriage is not.
And it gets even worse. Remember that the invalid baptisms began about 27 years ago now - and some adults will probably have been baptised during that time using the invalid formula. It is not impossible that one of the roughly 5,000 invalidly baptised men may have since trained for the priesthood. If so, their ordination is quite simply invalid - no question: you cannot be ordained if you have not been baptised. None of the Masses he said were valid, he never gave valid absolution and he never validly conferred the sacrament of anointing.
At this point, I am sure that somebody will want to say "Hang on, God is very nice. He's not going to condemn people to hell because some stupid priest said the wrong thing all those years ago." So OK, to pre-empt such comments let me say that I don't think any of the victims of this injustice are unwittingly going to hell or that they do not receive any grace etc. etc. But God became incarnate. He founded a Church and he instituted seven sacraments for the Church, all of which have real spiritual effects. Of course, God will look kindly on the innocent victims of disobedience. But grace is from God and he gave us the sacraments which the faithful have the right to receive when they are properly disposed. Thousands of people have been denied that right. The Church can supply jurisdiction where there is common error or positive doubt. But it cannot supply grace or the sacramental character. People have been subjected to an injustice here: and all because somebody would not
To give one practical example of the consequences of this injustice, if there are invalidly ordained priests as a result of the invalid baptisms, there will be a whole lot of Mass stipends taken for what will have been invalid Masses. The people who gave the stipends have a strict right in justice to have those Masses said. Somebody should pay stipends for those Masses to be said. It would be a fitting thing if some estimate were made and stipends sent to poor priests in the missions to say however many thousand Masses "for the donor's intention".
Fortunately, Baptism is valid if adminstered by a layman with the correct intention. We can only pray that any invalidly ordained priest did not follow the example of his erstwhile pastor.