Controlling narcissist parent

So for the last year my mom’s been trying to get our family back together as we should be. She helped me through a rough patch while I was unemployed. However she constantly gets annoyed when I parent my child. She thinks I “bicker and bark at my son” when really he just doesn’t listen and I have to repeat myself.
And this she knows because she has to do the exact sammme thing! So recent events with that led to her saying I can’t scold my son in her house anymore. She said if he’s at the table and I’m not eating at the table and he’s doing something wrong she will take care of it. But either way I’m not “allowed to parent “ at her house. I really thought that was the most absurd thing she’s said in a long time.
Any thoughts or advise ??? What would you guys do?? Her need for control is really bad and sad actually now that I think about it. Either way I’ve refused to go in her house anymore (again) until we go back to therapy because this is ridiculous. She only does well when we are in therapy.