I am moving my husband with Alzhiemers to another home. He is vocalising a lot, when the Assessor from the new nursing home came to asses him, she said "He is not comfortable in that hard chair". She sent a picture of a chair. I went to the store and checked it out. Boy oh Boy! So comfy, so soft, gently rocking, warm, can recline. This is in South Africa. I could rock in that chair and go to sleep. Maybe it may help to get a soft reclining rocking chair. Just a suggestion. There is no way someone could slide out of it as made of soft fabric. Just thought I would write this. Hopefully it helps.
