She Sent Me A Friend Request

I got a friend request from my boyfriend's ex girlfriend. My boyfriend was in a super abusive relationship with this girl. He has really bad scars on his body. He refused to let me see his body the first four months we dated. He has a knife wound from where she stabbed him. It took him three years to get out. It took him a long time to open up to me about it. He goes to therapy to help himself through it. She sent me a friend request on Facebook and a message request saying "Hey". I was gonna block her, but I'm kinda curious on what she has to say. Should I just block her or hear her out?