Yes, I know this is confusing for women to experience, and I believe you have the right position. A man in his 60's has little to no chance of getting a woman in her 30's to marry him. Stats prove this, and I have had enough women tell me it is "creepy" to hear from a man 15+ years older to know that this man is wasting his time. And to maintain a hope of naturally fathering children at that age is probably ridiculous, and certainly foolish. He's just not thinking of the big picture, and lacks consideration for anyone but himself. It also could be a sign of arrogance to think that God continues to ask him to put off considering a good woman like yourself of his age group because God wants him to father children.
I hate to say this, but I am praying that he is just giving you "a line" to make it easier on you instead of just coming out and saying "I'm not interested," because the alternative is just not an alternative in my mind (which is that he really believes he will find a much younger woman to marry him and give him children). And I am talking about "Catholic" women here. Perhaps there are "gold digger"-type Catholic women out there who will welcome such a union for the purpose of inheriting a bundle of money once he is dead (10 to 20 years at the most might seem like a good investment to some 32-year-old women), but gold diggers don't tend to want to be "mothers" of the children of men that much older. And this is all assuming he is a rich man, which I am doubting.
Passing up a women of his age in hopes of a younger woman of child-bearing years is delusional. How much time does he really think he has left to live in this world, let alone to wait for this woman to come along? His delusion will very likely take him to the end of his life having never enjoyed the companionship and love and devotion of a good woman like yourself who, though you cannot give him natural children, could give him happiness like he has never experienced, and give HIM the opportunity to live the vocation God called him to, which is to serve. I am always amazed that there are some people out there who look happiness straight in the eye and pass on it.