Sister Got My Alzheimers Diagnosed Grandfather To Do A Quick Deed Sign Over To Our Mother’s Home.

Location: Tennessee Hello I’m a 30 year old with a 32 brother and a 36 sister. Our mother had built a beautiful home near our grandparents when I was in elementary school. Unfortunately my mom battled with drugs leading my grandparents to take over the house many years ago. About 11 years ago my older sister had bought a house about 40 minutes away. My grandparents were putting my mom’s house for sale for $200k. When my sister had a baby, her and her husband moved into my mom’s house to be close to family. A year or so later my sister and grandparents came to an agreement that the house would be left in their will/trust to all 3 of my moms kids and she would have to pay us off if she didn’t want to sell the house and split it. She had talked about getting everything settled before my grandparents would pass. She would make loan payments to my grandfather to pay us off. That never came to fruition. She sold her house she owned and my sister and her family lived in the house completely free for about 8 years. My grandfather was diagnosed with Alzheimer’s/dementia and started going downhill. 3/4 years ago my sister went to my grandfather and told him they only way she could pay my brother and I off is to get the house in her name so she could get an equity loan on the house. Around that time I also wasn’t in contact with her for other personal reasons. It’s been 3 almost 4 years and her attitude completely changed after that. She cut my grandparents off from contact with her or the grandkids and anytime they stop by they lock the doors. My grandmother stopped by to talk to try to get something figured out and her husband said they would call the cops if she didn’t leave. My grandmother is very upset over all this. My grandfather didn’t even remember signing the house over a week after it happened. Can anyone give advice for what type of lawyer to contact or any information we will need?