That doesn't even make sense unless he's locked her up in a basement cage.
Otherwise she'd come out saying it's not her.
If it is a sock puppet then she's agreeing by not saying anything which means his mom does appreciate his work and approves of this and it's not a 'version' of her.
Why would she bother? If I said my parents said crazy stuff, my parents probably wouldn't notice or care. I don't have a Twitter/X account, nor do I follow it, and the only exposure I get is here. If someone started saying crazy stuff about me, I probably wouldn't notice, and if I did, probably wouldn't care enough to correct the record publicly.
And no, I'm not extremely rich or famous, but even if I was, I wouldn't expect my parents to step in if I started doing stupid stuff, unless that crossed into slander or libel or something.