So this is a long one..
My grandparents are both in their 90s and are the most amazing people that I will ever know.
My Mum and Dad got divorced 21 years ago when I was 4 as my dad had an affair but my mum has always remained very close with my dad's parents as she has known them since she was 16. They were like second parents to her after her own parents died.
Recently, both my grandmother and grandfather have been having health problems and me and my mum and my step-dad have been helping them out by getting their shopping, taking them to appointments. We visit them at least twice a week and my mum speaks to my nan every day.
My dad now lives in a different country with his new wife and their daughter and barely phones his mum or dad or me but gets so mad about my mum and step dad being in contact with his parents even though my mum has never done anything wrong he hates her.
I have just found out that my dad has literally screamed at his sick mother about being in contact with my mum and her new husband.
He has told her that if she leaves them anything in the will then he will contest it in court.
My nan didn't want me to know about any of this so has kept it from me until yesterday when she told me everything and told me about how upset she is with it all.
I guess what I am asking is am I being unreasonable for being mad at my dad?
I don't know whether to confront him on it as it happened months ago and my nan has begged me not to say anything to him but I am so angry that he has upset her like this that I feel like I can't just sit back and do nothing. Also, I need to defend my amazing mum in all of this..
what should I do?