My mother-in-law yelled at me for following her to her room. What do you suggest?

I'd give her more space. The walker itself is intrusive enough w/o having someone follow you around. She's losing independence, but there's really nothing you can do to change that. She will still fall.

What the Dr. meant was "keep an eye on her'' and that's all you need to do.

She 'shouldn't' be allowed to go to her own room without you watching her? Or you'd rather she didn't?

Honestly, she's going to fall whether she's followed like a Border Collie or not. My mom has fallen with people right behind her and not one single time did any person 'help' her to keep her from falling.

Elders will do as they please when it comes to using a walker. You can't be on the woman like white on rice and expect her to be grateful for you hawking over her like that. Nobody would like it, including YOU if you were honest with yourself.

Keep an eye on her, then let the chips fall where they may. Whether she "MUST" use her walker or not is up to HER, in reality, since nobody can force her to.

Nobody can prevent an elder from falling, no matter how closely they're watched. I know...my mother fell 95x in the last couple years of her life. 😣

Get her placed in Assisted Living if her care and management become too stressful for you at home. That will give her autonomy and a life of her own, and it will let you off the hook for babysitting her 24/7 which is too much for you.

Good luck with a difficult situation

You cannot watch someone 24/7. I can appreciate what you are trying to do but all due respect - you ARE driving her crazy! It would drive me crazy too. There is something that happens with people with dementia and frequently their caregivers called Shadowing - where they follow them around all of the time. That is what it sounds like you are doing to her, in reverse. They cannot help doing it to their caregiver. It is a symptom of the disease. But you can.

I know you are just trying to help her. But what you are doing is frustrating a woman who is already incredibly frustrated with her life and her circumstances. You can be literally on top of her and she is going to fall. You cannot prevent 100% of her falls. I know you mean well. I REALLY do. But I think you are being a little bit too literal. And you are going to wear yourself out. And you are going to provoke her unnecessarily in the bargain.

Please give her a little bit of space. A better use of your time might be safety proofing your home in places you know might be more dangerous. Taking up any loose rugs. Putting up corner guards. Putting up grab bars. Putting no slips in the shower. Making sure she doesn't wear socks. Or if she insists on wearing socks make sure she wears shoes OR no slip socks. Make sure her walker is nearby and encourage her to use it.

But don't follow her everywhere she goes. Don't ask her why she does literally everything she does. Treat her like you would want to be treated. She is still an autonomous adult with feelings and needs. Would it get on your last nerve if she followed you everywhere (Because that might be coming - my grandmother shadows my mom and my mom can rarely catch a break - and she doesn't want anyone but my mom). Let her do what she can still do for herself. ENCOURAGE her to do the things she can do for herself. She NEEDS that. She needs to feel like she can do things for herself.

You can't prevent every fall. There is no 100% perfect scenario.

Falls happen...no matter how careful. Worked as a nurse in a nursing home at one time. Had a lovely lady - and she had developed balance issues, along with dementia. She started to fall over - from a standing still position. Unless you were close enough and quick enough to grab her in a bear hug before she went down...it was too late. Not possible to keep her in a WC all the time (no restraints permitted) unless we sat right with her...or to get her to use a walker, either.
So we just tried to take turns taking her for long walks to tire her out, which helped a bit, and soon she lost interest in walking at all. For her, progression of disease kept her safer. Sad.
Yes, your MIL may fall right in front of you, or in her room with no one else present. Yes, falls often lead to the death of an elder, Given her diagnoses of Parkinsons and dementia, her quality of life is not going to get better. So perhaps letting feel relaxed in her own home is kinder to her....quality of life for her, and realistic expectations of you.

I hope you are getting paid to be MIL's caregiver.

You won't be able to prevent her from falling everytime and you may injure yourself trying to stop her from falling.

If she wont use her walker there is not much you can do other than tell her if she doesnt she can no longer live in your house.

Stubborn old people are fools.

It is your MIL so I would say your husband has to have serious talk with her about the way she treats you, you cannot let this escalate.
I am caring for husband with Parkinson but no dementia, so he does not have those outburst. But, if on rare occasions meds are not on time his walking becomes worse. Also, is it possible with dementia she forgets about walker?
So you remind her and she gets nasty. Time for serious talk and for you to decide if you can do it alone if that is the case.