Is it normal that my mom has talked about suicide for as long as i can remember

My mother has always threatened me with suicide ever since I was I little. It has always terrified me and caused great unneeded anxiety. My father always ignored it and went to work etc. Recently, my sister and I confronted our mother but she just said she didn't have to talk to us and then threaten us with her death, again. Our father afterward was calling us spoiled brats who wasted our mother's life. We were just trying to get her to do therapy. Afterwards, I spoke with my mother and she told me that she has never acted on this and uses it as an expression. Problem is my sister and I grew up hearing this and have it imprinted in our minds as a solution. Is this normal? What is wrong with my mother???