What can I do when my mother-in-law needs help but refuses it?

We have the same problem, only my monther-in-law came to live with us because the hospital would not release her home after she became ill. She is now causing such disturbances that we have no choice but to send her home, before she wrecks our family. We have done the 3rd party intervention with the doctors even putting it in writing, but she will not accept a nurse, or go to an assisted living place and does not want to stay here - she won't try to make herself part of the family.
We have contacted meals-on-wheels and are going to arrange for food to be delivered a few times a week, and a company called VRI to have her medication monitored. It is an automatic monitored pill dispenser. The only thing we can't figure out how to monitor is the motrin. She gets frequent mirgranes (which she has had much less frequently since she's been here) and has 800 mg prescription strength motrin. We found out that she had been doubling up on them and think that's what landed her in the hospital, but aren't positive. We've been monitoring them while she's here, but need to know if anyone knows of a pill system that will only open every 6 hours, but not alarm her, so that if she doesn't take it, she doesn't have to.
We just don't know what else to do, as she's still somewhat competent and certain things and forgets other things.
If anyone has any other sugestions, we could surely use them.

We have tried the objective third party, to no avail. On two different occasions, separate appointments with her neurologist and her family physician, my mother-in-law was told by each doctor that she should no longer be living alone and that she should consider moving to a facility where she could get help AND have more interaction with people. On both occasions my mother-in-law informed her daughter, after the appointment was over, that she no longer "liked" that doctor and said that she would never go to that doctor again.

She no longer knows how to cook for herself, so we shop for her and see that she has sandwhiches and other food items that she can eat without any required preparation

Take a look at this article on "Determining if Your Loved One Can Continue Living at Home." It might have some tips that will help you. Also, having an objective third party (i.e. a non-family member, such as doctor, care manager, etc.) speak to the elder often works wonders. Sometimes, people will heed the advice of a near stranger, over the same advice from a family member. Go figure!

https://www.agingcare.com/articles/should-elderly-parent-continue-living-at-home-95665.htm