I think I'm going to comment on facebook to see if my dad was pretending I don't exist.
Why do you want him to know you exist?
I Think it's better to let him know I exist and that he has a son.
It's morally wrong for you dad to be ignoring you and acting like you don't exist.  Your father's actions can have a profoundly negative impact on your development and mental health, so if he loves you he should acknowledge you and want to have a relationship.
Why don't you give a fuck about my dad.
Sorry I think you misunderstood me. I'm just saying that your dad should never pretend like their kids don't exist and you should talk to him about it.