How do I find a dementia/stroke rehabilitation?

She might need OT, when my father had a stroke he went to clinic that did both PT and OT and did regain much of his control back.

Though OT and PT is probably extremely rough if not impossible for someone with dementia or ALZ.

Does rehab understand that she has dementia? I guess they just have to repeat the instructions every day, like ground hog day. If she is making progress, it is because she is doing the exercises, not because she can or can not remember them.

My mom is the same way at home. Have to tell her every time how to do something. Oh well.

Marmo, it's hard to make recommendations w/o  knowing the area in which your MIL lives.    E.g., Michigan has a Rehab Institute of Michigan, which used to and may still be affiliated with the Detroit Medical Center hospital group.   It offers stroke rehab; I saw one stroke patient working out when I had rehab there several years ago.  

Just FYI, and what to look for:
https://www.rimrehab.org/

Providence (now Ascension Providence) Hospital also provides stroke rehab in its very well staffed rehab facilities.   

But these are Michigan facilities.   

This provides good information on finding a stroke rehab program:
https://www.stroke.org/en/life-after-stroke/stroke-rehab/choosing-the-right-stroke-rehab-facility

and

http://www.carf.org/home/

Commission on the Accreditation of Rehabilitation Facilities (CARF) provides a link to rehab centers with stroke recovery programs:

Find a provider near you:
http://www.carf.org/providerSearch.aspx

When you contact facilities, ask if they provide stroke rehab for persons with dementia (as already addressed by NYDIL and JoAnn).

The problem is not the rehab but that ur MIL has Dementia. They need to remember so the PT doesn't have to teach her the same thing everyday. They have to be able to have some progress. Had the same thing with my Mom after a hospital stay. PT was just to get her strength back. She could not remember what the therapist showed her.

Your profile says that your mother also has Alzheimer's. Perhaps that is why "she's not able to understand what they are instructing her to do"?