That's the legend. It's a lot less clear-cut if you actually listen to the recording. We don't actually hear her saying it. There's a lot of confusion and people yelling, and the interviewer claiming that's what she said when it's not clear that she did. McRae keeps switching between "your son" and "your grandson" so it wouldn't be surprising if she were confused.
When this story first came out, I rushed over to the website that was announcing the scoop and I listened to the audio recording.
The woman obviously did not speak English, the Guy asking her the question made it deliberately leading and confusing, and when the woman said "Yes" he interpreted this as "proof", despite the fact that once the question was repeated to her once more in her own language, she then adamantly said "no."
It is not at all cut and dried. It was clearly an attempt to set her up to agree with him, and she did initially but immediately recanted that answer.
I wanted this story to be true, but I have to say this myth is busted.