I'm thinking of my mate getting in trouble with his parents
What's wrong with their relationship?
I'm going to deface a photo of his parents
This matter is entirely out of your hands. You shouldn't be messing with their photos as their friend. Your friend may be hurt if he knows you are doing this.
He deserves it for what he did to me.
I can understand being upset with your friend for what he did to you but you should not mess with his family. It is bad to mess with his family and he might not forgive you.