Wrong, I read it on another thread. He didn’t say that the RC church is the only true church and that all others aren’t?
I think what we have here is a difference in our definition of "church."
All Catholics believe that the Catholic Church is the One, Holy, Catholic and Apostolic Church which is spoken of in the Nicene Creed, which every one of us recites every Sunday: you can find that HERE, and it's well worth reading in its entirety.
As the Catechism explains, we believe that one ordinarily joins this church by Baptism. Thus all who are baptized are, in a fundamental sense, Catholic. But not all the baptized hold and believe the fullness of the Catholic faith; yet these too are members of this One Church, exactly to the degree that they do profess her Faith (one Faith, ine Lord, one Baptism.)
So it's not an on/off position. It's a matter of degrees.
To see this perspective, you can read this in the Catechism:
"The Church knows that she is joined in many ways to the baptized who are honored by the name of Christian, but do not profess the Catholic faith in its entirety or have not preserved unity or communion under the successor of Peter."
Those "who believe in Christ and have been properly baptized are put in a certain, although imperfect, communion with the Catholic Church."
With the Orthodox Churches, this communion is so profound "that it lacks little to attain the fullness that would permit a common celebration of the Lord's Eucharist."
My dear husband, who is without question a better Christian than I am, by far, was baptized in the Baptist Church and also in the Orthodox Church. (Double dunkin'!) Just by virtue of baptism, the Catholic Church would say he is certainly, but imperfectly, Catholic.
(Ducking a flying biscuit....)