By all accounts, she never went to her Dad's house. And for that matter, she never went to her friend's house either, and in fact, there was never a plan for her to spend the night with her friend.
The sleepover story didn't come from CD, but from SA, and he supposedly was the last one who actually saw her. That's his story - no one forced him to tell it that way. He also told the story about Hailey saying she was going to walk to her Dad's, but considering the source, that was probably a lie also.
There's a reason many of us are looking at SA instead of the Dad. It's all about his story and how it doesn't check out.
Let's also think about this: CD has a past of small-time drug abuse (not that unusual in the world). SA has a history of small-time drug abuse (on video!) but also collecting freaky horror movie costumes, a fascination with knives, and says he threatened Hailey before. Sounds like the right suspect to me! JMOO