to Heaven, but they can not accept that Mary helps everyone to get to Heaven. -----W-----
The mere fact that Mary agreed to accept the great glory - and the great agony - of being The Mother of God, is enough for any sane person to realise that she is most certainly the supreme co-operator with her adored Son, in His Salvation of all creation.
So, the facts are simple:- each of us must co-operate with Jesus Christ to gain His Salvation;
each of us is able to assist another to gain Salvation;
therefore, Mary is also able to assist another to gain Salvation;
but if Mary was the only instrument and the only avenue by which Christ came into creation as Man, as well as being His prime assistant during His Life, then clearly Mary is able to help everyone to gain Salvation.
Just as Scripture states in Revelation 12 where Mary is positively shown to be the Mother of all of those people who follow Christ. Being Mother, Mary very obviously assists her children towards Salvation.
Mary is Co-redemptrix - simple.