You can have your mother assessed. If it is proven she has dementia and/or alzheimer's then her will may be null and void. I recently spoke to a lawyer regarding this matter as there is a similar issue happening in my family and I want to be sure it doesn't happen with me. Has anyone been given Power of Attorney to see that her care is paid for when she is unable to make those decisions? Have you spoken to your mother regarding her decision? She may have been pressured for some time before the attorney entered the picture.