Hi David,
I know a little of what Michael is going through because I get frustrated with my Mom sometimes. Luckily, maybe it's my age, I am able to step back and catch my breath before I really hurt her feelings. I think we do it out of fear more than anything. It sounds like you need to have a counselor involved. Do you go to church or have a church family that could intervene a little bit? What about other friends or family members? I can't imagine how awful this all makes Linda feel and as her hubby you need to just step in and put your foot down. She needs you to be her voice if at all possible. Not that you probably don't already know this, but maybe you feel you shouldn't because he is just trying to help. But that kind of help is doing more harm. Like you said, doing something slightly off is better than belittling Linda.
I'm so glad you know we are here for you. I love that we can vent to each other.
Kathy