The first thing to think about is what you hope to achieve by replying to him, and whether this is achievable
My dad is in his 70s and has contacted me on Facebook. I have not yet replied. I last spoke to him almost 20 years ago, shortly after my mum died. I was 17, and he was angry with me for ignoring him. In my early childhood my dad lived with us only briefly, but was often drunk and angry, and I heard stories of him hitting my mum.
My mum left him when I was four and I saw him again when I was eight, when I was expected to keep him company; if I didn’t he would go to the pub and get very drunk. One time I went to play with my friends, and when I came home he was so drunk he hit my mum and threw my dog against a painting. That day I decided I hated my dad.
