Hi Cristo…
It gets down to our understanding of Christ as True God and True Man, how the Church was founded and organized…and the other, history is very complex and it depends on whose angle you are reviewing.
I mean to say, you have to get into some deeper concepts than that which exists at the level of JW’s…so that you end up sharing correct information, correct overviews of history…but it will go over their heads.
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I think the best way is may be to give them teachings on the Catholic understanding of Christ…and access the universal Catholic Church Catechism. It can explain alot…read how Catholics approach Scripture and how we see it as a whole, rather than taking out parts…that will contradict each other. Very overwhelming…history, too.
Best use the catechism…in context…use that as the basis…starting from the beginning…and show the parts of how it is organized…the footnotes…showing how it is based on so many passages of Scripture…shows early Church Fathers teachings, councils, synods, etc…and its use of dates and time.