I think the point is that when you ask this type of question, it encourages the stalkers to reply. We don't like the stalkers. Stalkers are bad. The rest of us really don't know what's up with the Queen mums.
Brian's mum passed away a couple of years ago, not too long after his dad I believe.
I also believe Roger's mum died a few years ago.
As for John, well, who knows? I'm not even certain the man himself is alive....