I am so sorry Beth Ann. I lost my Mom, my best fashion friend, last summer, after a very long battle with dementia. There is a LOT being explored about this kind of condition and there have even been a couple of first person accounts published. I would look for those and see what they may offer. You may want to prepare yourself to fight against letting the Diagnosis cloud who your SIL is, herself. Dementia robs us of a lot of our personalities, and yet I think in many ways those likes, dislikes, and quirks are probably still inside us, it's just confusing for those around us. I really hope some of the newer approaches can help your family and stave off some of the worst, scariest symptoms. I know it's hard and it has to be crushing to have someone so young in the clan stricken. Be strong, but also be kind to yourself, it's a difficult path.