First off, I am positive that many, many Roman Catholics do use artificial birth control. And as for your statement on failures, sure, they happen but I don't think that's a problem with men and women "of a certain age" (your words).
Oh yeah, there are fail-safe means of avoiding pregnancy. They are known as vasectomies (in men...maybe you've heard about them) and "tube-tying" (I don't recall the exact medical term) in women. 100 percent fail-safe.
I am familiar with those procedures, which are forbidden to believing Catholics. Not everyone takes his faith lightly or supposes that the rules don’t apply to him.
The point is, not everyone thinks that a child who is conceived when the father is 50 is sorry about it. Some of us consider it a great joy and blessing.
What difference does it make to you, that these people had a child when Dad was in his fifties? Apparently neither the father nor the daughter regrets her life. In eleven years she will have more time with her father than millions of young girls will have.