Remember that the issues are at bottom, spiritual; and not intellectual, institutional, moral, or anything else (though these aspects can and do play parts, and may be raised up by one side or the other as relevant in discussions).
Your love for your RC relatives and friends, flowing from your love of Christ, combined with the fruits of the gospel in your lives (as they come to be seen), will be the best "book" they read; even if you find other helpful resources. Its the kind of material that may take the longest time to digest, but it has deep effect.
There are
lots of
different RC-isms out there. That's probably not news to you, coming from that pool; but many people inside and out RCC believe the rhetoric of
semper eadem, "always the same," that RCism is the faith that never changes, and never has changed.
Quod semper, quod ubique, quod ab omnibus creditum est. Except... that Rome has changed over and over again. The fact is that within the past week or so, it has morphed a little more with publication of señor Bergoglio’s
Amoris Laetitia. That roaring sound in the background is competing
RC voices explaining that or how this latest pronouncement has-or-hasn't changed the unchangeable; and what it all means for the "faithful."
Who are the modern RC "faithful," and can anyone tell the difference apart from some overriding commitment to the theory (rather than the current instantiation) of the papacy? Which previous set of dogmas, from which era, are the "gold standard" of RCism? I have encountered a few "Old Catholics" (perhaps represented institutionally best by
https://en.wikipedia.org/wiki/Old_Catholic_Church ) whose rupture with the Vatican dates to the 1870s; and others from SSPX (
https://en.wikipedia.org/wiki/Society_of_St._Pius_X ) another breach from the 1970s. The Jansenists (strict predestinarian Augustinans, opposed to Rome's semi-Pelagianism) were suppressed even further back, in the 1600s and 1700s.
Anyone who appeals to "the way things were in the beginning"--as the Protestants did in the 1500s--faces a choice: reformation or accommodation. One today in RCC, though he dissents from his leadership's direction as a matter of conscience, he will most likely be let alone.
Provided that he remains "loyal to the Church," which in Roman parlance means only the communion acknowledged by the bishop of Rome.
A RCer who thinks his bishop or pope is teaching anything improperly on any grounds whatsoever, he explicitly or implicitly challenges the submission that is required of him. Someone of lower "rank" is not entitled to decide what is or is not within his superior's scope of moral or doctrinal purview. For example laymen who declare the pope is beyond his authority when teaching of morals impinging the realm of economics, they presume to fix a limit upon the man who (in RCism) gets to determine the limits for himself. Allowing or getting strict with dissenters: these are simply prudential choices of the powerful hierarchy which (though often bickering within the ranks) has shown itself capable of uniting for self-defense, or being united by a charismatic leader (an ecclesiastical potentate) with a strong will.
A key piece of Roman dogma is that "nothing is fundamentally wrong here, because nothing
can be fundamentally wrong here." This is the one, immovable certainty of Romes self-understanding.
"Trust us (you have no choice)" is Rome's essential creed. No bishop = no sacrament = no salvation.
Rome imagines herself as an "ongoing Incarnation," with the Pope as the Head of his body. With this understanding, there can be no "schism" that continues to live; there's no
lesser part capable of carrying on with the true life-of-the-church not flowing down from the top. This is what happens when Christ is removed as the true and ONLY Head. Corruption that gets to any earthly head cannot be recognized, dealt with and separated.
Rome IS a departure from the Faith. They are the schismatics, because they are irreformable, by their own admission:
There's nothing fundamentally wrong with us, even if you find bad characters inhabiting the church.
If a genuinely faithful layman or churchman cannot appeal to the present body, to a dogmatic confession, to church history, or to the Bible (ultimately)--if he cannot LIVE a faithful church existence along with those who share with him conviction of the true gospel--this is death. One cannot live a lie without dying. Rome is a mostly dead place, and so to live one must get free.
Look at our Confessions. They tell us that it is possible to find an expression of the true church--ruled by Christ, his Word and Spirit dominant. The sacraments rightly understood and administered for the benefit of the people. And discipline faithfully, ministerially, and impartially practiced. These are what a true Christian wants, besides that essential need for peace with God who is otherwise estranged from us.
We believe that we have no access unto God but alone through the only Mediator and Advocate, Jesus Christ the righteous; who therefore became man, having united in one person the divine and human natures, that we men might have access to the divine Majesty, which access would otherwise be barred against us. But this Mediator, whom the Father has appointed between Him and us, ought in no wise to affright us by His majesty, or cause us to seek another according to our fancy. For there is no creature, either in heaven or on earth, who loves us more than Jesus Christ; who, though "existing in the form of God," yet "emptied himself, being made in the likeness of men and of a servant" for us, and "in all things was made like unto his brethren." If, then, we should seek for another mediator who would be favorably inclined towards us, whom could we find who loved us more that He who laid down His life for us, even "while we were His enemies?" And if we seek for one who has power and majesty, who is there that has so much of both as He "who sits at the right hand of God" and "to whom hath been given all authority in heaven and on earth?" And who will sooner be heard than the own well beloved Son of God?
Belgic Confession, Art.26, Christ's Intercession, first para.
Luke, your departure makes the people you love fearful. What if you have made the right choice? Then they may be in trouble themselves. A painful choice may be part of their future, too. Better (?!) not to dwell on that... Much easier to mock and rebuke you, for now.
But you hopefully have time to bear with these friends of yours. Time to show them the grace of God at work in your life and the life of your family. I personally think that sticking with the Bible in your interactions with your loved ones, and occasionally showing them some relevant portion of your Confessional commitments (as in the Westminster Standards or the Three Forms of Unity) will be more in line with your purpose than a book or a pamphlet.
Apologetic websites often have resources for answering RC questions and objections. Their articles and posts are almost always helpful for strengthening your own hope, no matter how "effective" they seem in the application. Remember, it isn't a matter of the intellect. "What do you have, that you did not receive?"
Hope these thoughts are helpful.