I live with a hubby who's only home on the weekends and a grown son who is mainly here after I go to bed at night. (He's a gluten eater and not the least bit careful).
My hubby tries to be aware of spreading gluten around, but sometimes he forgets or isn't careful enough. For a while I had to call him back to the kitchen after he "cleaned up" and show him what he had left behind so he'd learn. The way I approached it had to be in the right "tone" or he'd get offended.
I can never assume that the counter or stove I wiped down after cooking is clean. I never lay anything on the bare counter. I use paper towel/paper plates a lot. I have separate plates, bowls, and silverware that I hand wash after eating rather than put them in the dishwasher. I've seen plenty of dishes come from the dishwasher with "stuff" on them so I don't trust it.
I had to get my own microwave because the shared one always has crud in it.
It's extra hard when you aren't the one in control of the kitchen. The colander is dangerous to share. It's impossible to clean all gluten from it. Wooden spoons and cutting boards can hold gluten too.
I hope you can find a way to help your Mom understand how trace gluten can keep your system upset and prevent healing.
Perhaps she's finding that gluten *might* be affecting her and that's why she's so bullheaded about gluten being so dangerous? She may be in denial/scared about how it's affecting her as well?