We need to find a simple microwave that my mother can use. Need auto shut off as she falls asleep during process. Recommendations?

The inability to remain attentive to the microwave task is a bigger problem than it seems. A simpler microwave is a workaround, but not a solution.

When my mom couldn't handle the microwave anymore, it was time for her to move to the assisted living unit, out of her independent senior apartment. This was one of many signs. She ended up skipping assisted living due to some major incidents that happened.

She also was not able to handle other process/sequential-step based tasks. The microwave thing was not happening in isolation as a freak problem.
She could not keep her bills paid (but said she could), her medicine sorted and taken correctly (but insisted she did). She could not do her laundry or keep her fridge cleaned out of rotten food. She could not write out a check, or address an envelope, which is why bills weren't getting paid. She couldn't make sense of the Rx bottles.

Keep your eyes, ears, nose, and brain open to look for other small things that may no longer be in order anymore. The laundry, the trash, piles of clothes or laundry that can't seem to be put away, piled up dirty dishes in the sink, home repairs that aren't getting done. One thing tends to lead to the next.

Most home delivered meals for the elderly are pre-cooked, but arrive cold. (Beacause the drivers couldn't possibly deliver all of the meals hot). Most "meals-on-wheels" services for the elderly expect that the elder will (re)heat the meal in a microwave oven. However, many elderly, due to dimentia, alzheimers, "senility", etc., make mistakes in selecting the cooking time. E.g. pushing the buttons 1-0-0-0-start, which results in 10 (TEN) minutes cooking vice the desired 1 (ONE) minute cooking time will often burn the food and container to the point of fire or near fire. My mom does this often and walks away as soon as the buttons are pushed to do something else while her food cooks. So when it starts to burn she is not there tom see the danger, and has forgotten that she has food in the microwave. (Until her hunger tells her to go to the kitchen again). This is very common among elderly. What is needed is a SIMPE microwave that has just 2 (two) buttons: 30-second, and 1-minute. The microwave would only cook for that amount of time (at only one power setting) and no more (i.e. no cummulative time setting capability). If the elder has to run it for multiple cycles for a larger meal than the typical "meal-on-wheels", then so be it. At least the home won't be burned down with an elderly inside.
Why dooesn't some manufacturere make such a microwave: do they think there is just not enough money in it? One would think that todays elderly numbers. along with the baby-boomer retirees, would provide a large enough market.

What is required is a microwave big enough to hold a dinner plate, with one button to press that says "reheat" and a built-in reheat sensor. Also a big display that counts down the minutes left, says "ready" when it is done and beeps repeatedly until the door is opened. There is a huge market out there - the worried children of forgetful parents not yet in care.

If you've had to disconnect other appliances and you've already had fires no microwave is safe for her to use unsupervised.

One of my clients' adult son put stiff white paper over all the settings, except for the one which shuts off after three minutes. His mother accepted that solution. Now she no longer remembers how to use the microwave, I thought his solution was ingenious and super cheap. No need to buy another microwave.

Perhaps the alternative would be to have home-delivered meals brought in to her. Your local Area Agency on Aging could help you out with this process. Most programs for home-delivered meals have a no-cost/donation only program for elderly individuals. I work in the industry of elderly care and haven't seen or heard of any such microwave that would shut off in the event of burning food.

If we all write to companies expressing the need for a simple microwave for elders, perhaps they will make one. Im going to contact panasonic, Whirlpool and other companies. I will send email addresses of those companies so each of you can contact them too. There is power on numbers.

My mom's was marked at 2 minutes. She would turn it up all the way any way.

We had a simple Kenmore, but when it went out, the new Kenmores were awful. The buttons are hard to punch and almost impossible to read -- little contrast. They changed the punch format from simple to complicated. I have no idea why they went to such a terrible appliance when they had a fairly simple and good one before. Kenmore has been scratched off my list for a replacement if we need one.

If I were buying another microwave, I would go to the store and look for one with a panel that is easy to read -- big writing with good contrast. I would look for one with a simple panel without a jillion options. Then I would get online and read reviews about the product. Of course, there will still be surprises if you buy it. We never know until we open the instruction book that you have to turn around three times, then bark, before entering a complex series of panel pushes.

What my Mom did any time she had anything cooking in the oven, on the stove top or in the microwave, she would set her LOUD portable kitchen timer and carried it with her. It was a standard routine for her the past 70 some years. That thing would scare the daylights out of you :P