Forgiveness isn't about minimizing the past, it isn't even about the other person, it is about severing the pain that ties you another person.

The goal is to have the freedom to make choices in life that are good for you. Choices that are uncontaminated by painful memories.

Trying to decode the postings on your dad's facebook page is a continuation of your childhood. You didn't understand him then and you don't understand him now. You may never understand him.

Have you considered saying "I don't need to do this anymore" and stop visiting his page?

Understanding is not a prerequisite for moving on.

You can always try to figure him out later.