Get a copy of “Catholicism and Fundamentalism” by Karl Keating … on the “shop” button at the top of the page.
It’s an outstanding book … was originally published as a newspaper serial set of very comprehensive columns.
The book lays it all out.
Also, there are the tracts … visit the Catholic Answers Home Page … on the row of buttons at the top of the page, on the left side, click on “faith”. and then scroll down to the bottom of the page and there is a large box marked “tracts” … click on that. They’re free on-line or if you want to, you can visit the “shop” and buy a set.
I’m not sure what you can say to someone who is that set against the Catholic Church.
My experience is that after I have been humiliated a few hundred times, and after I have thoroughly beaten my self up a few hundred times, “suddenly” thoughts and words start to jell and once in a while something actually starts to work right. It’s what people in show business call being “an overnight success” after decades of frustration.
You could say that the Catholic church is 2000 years old.
Ask if he has a set of the letters and writings of the early Church fathers.
[There is a book store called Stella Maris in Fort Worth, Texas and in their catalog they have listings of the early writings that will take a whole room if you bought them all, but having the list is useful to wave at them.]
Karl Keating also wrote “Pillar of Fire” which is a pamphlet and he wrote “What Catholics Really Believe” … and you can get both at the “shop” button.
Basically, the best thing is just to immerse yourself in the New Testament.
Read John 6: 20-70 a bunch of times. And you can just interject, “Well, you know … ‘unless you eat my body and drink my blood …’” … And that may start the ball rolling towards a discussion … any discussion.
And a useful tactic I have found is to ask if they have a bible and ask them to help you find John 6. And then kind of read it and when the people Jesus was talking to walked away, point out that Jesus DID NOT SAY: “Just kidding” … and try to persuade them to come back.
The response I get is “Oh, well … you’re taking it literally” … And I say something like, “how else would I take it?”
It takes a lot of practice … and you need to be able to swing with the pitches.
And pray to the Holy Spirit several times a day … ask for direction and guidance and, when you are in spiritual hand-to-hand combat … for the Holy Spirit to put the right words on your tongue. You WILL BE AMAZED … at the brief one or two word or one sentence exclamations that come out of your mouth.