I believe he spoke about it in his recent autobiography.
I think I'd have to see exact quotes by Graham to get the full context of anything he may have said about Catholic teachings. I did a bit of googling but the most specific thing I found was this:
Graham:I'm not in disagreement with anything he said there.
The primary way of communicating is to live the life, let people see that you're living what you proclaim.... [comments on his friendship and conversations with Fulton Sheen] I lost a very dear friend, and since that time, the whole relationship between me and my work, and you and your work, and the Roman Catholic Church has changed. They open their arms to welcome us and we have the support of the Catholic Church almost everywhere we go. And I think that we must come to the place where we keep our eyes on Jesus Christ, not on what denomination or what church or what group we belong to.