Protestants have a very skewed understanding of Catholic doctrine. The Catholic church in no way, shape or form believes or teaches that Protestants are not Christians. Or that Protestants will not go to heaven. Its simply not so. Hey Pope Francis thinks your dog Muffy is going to heaven so not to worry. :-)
Pope John Paul I, in a general audience on September 13, 1978:
"It is not possible to say: I believe in Jesus, I accept Jesus, but I do not accept the [Roman Catholic] Church. When the poor Pope, when the bishops, the priests, propose the doctrine, they are merely helping Christ. It is not our doctrine; it is Christs [where in Scripture??]: we must merely guard it and present it."
Moreover, Pope Paul had promulgated a whole new doctrine: Mary is the Mother of the Church.
As to our destination when checking out of this mortal coil, The Vatican doesn't believe Protestants OR even RCCs are going to Heaven (immediately, anyway.)
Most RCCs won't/don't/can't dig deep enough to understand or deconstruct its own liturgical maze which has been confusing by design.
On a lighter note -- Pope Francis' idea of Doggie Heaven will have Muffy sharing his Eternal Bone with Mitzi, Princess, and Rover. IN the same Doggie House.
;-)