My FIL (who has been diagnosed with Alzheimer's) lives at home and my MIL is his primary caregiver. He behaves terribly around her. Frequently, he will not eat or get out of bed. He gets "lost" in the house, talks nonsense, has delusions, etc. All the typical signs of Alzheimer's. But when other people are around, he behaves much better. He will get out of bed, get dressed, eat a good meal, make sense most of the time when he talks. He recognizes people he sees frequently but does not remember people he has not seen for awhile. He is checked on and receives visitors several times a week by relatives and home health professionals. My MIL calls my husband several times a day to report bad behavior. She does leave the house for several hours, twice a week, so she can keep her sanity. She is ready to place him in a memory care facility. I am afraid he is to coherent for such a drastic move. Does anyone else have a loved one that behaves differently around the primary caregiver than other people? Is it possible her attitude has a negative affect on his behavior?
And yes, every change does seem to set her back a bit in the progression of her disease, but it progresses regardless, unfortunately that is the nature of it.
Your FIL's behavior around MIL is his "natural" state of dementia. The show-timing behavior is "unnatural" under the circumstances and takes a great deal of effort.
I'm so glad that you can be supportive of MIL. She is in a very challenging situation. (Been there, done that, didn't like it.) It is really great that you are doing some research on her behalf.
Keep this in mind if FIL does go to an appropriate care center. He will quickly stop show-timing for the staff (although he may still be able to do it for a doctor who comes infrequently.) This may mean that his behavior seems worse after he's been there a few weeks. Many in the family may conclude that going into care has made him worse. Probably not. Very likely they are seeing the state his mind has been in for some time but that he has been able to hide from them.
I appreciate your help.