Go for it. Talk about all things you have in common and your faith in Jesus. Don’t talk about Catholicism, per se. Share what you have in common. Eventually you will get to disagreements and that is where your work begins.
Look to 1 Corinthians 3:1-2
Brothers, I could not talk to you as spiritual people, but as fleshly people, as infants in Christ. I fed you milk, not solid food, because you were unable to take it.
If he is just getting started, don’t overwhelm him. Let him grow and start to ask questions. Be patient as he goes from milk to food.