Once the human mind has accepted a powerful story - even though based on fiction - you will not convince them with logic, facts from scripture, nor evidence of any kind. They desperately cling to a falsehood rather than accept their understanding, life experience and cherished hopes are false.
In this instance, the pagan custom of praying to the dead and exalting poor humble Mary, and declaring some as “saints” while perverting the Biblical teaching of what “saint” means, will not end without God opening the eyes through conversion. All we can do is tell the truth in love.
The good news is that Roman Catholics are taught much that is true as a foundation.
And ALSO much that AIN’T!
That's likely a hindrance...They get the appearance of being right with a few things that are true while the rest, that which counts for their salvation is replaced with the fakery that their religion does so well...
Yet as the veracity of that rest upon the fallacious premise of the assured veracity of Rome, they believe other things which made the Truth of no salvific effect. To the eternal horror of those who choose it.