You should watch the video, btw he was 20 years old and had everything going for him, you can't tell me that you wouldn't have been in a panic. Many have gotten less years and have done more.
It doesn't matter if he was 20, 60, 18. He's a legal adult. He was willing to keep the woman's death a secret. 8 full days before telling police is proof of that. He made a poor decision and it cost him jail time. I don't always agree with court decisions, such as him getting more years than Brown, but that doesn't hinder the fact Dusty accompanied Brown to hide a body.
The article presents false information saying that he would only get 12 months of jail time for Accessory After the Fact. I had to double check because I've read something similar to this before a long time ago. Also, I just watched the video.
"Except as otherwise expressly provided by any Act of Congress, an accessory after the fact shall be imprisoned not more than one-half the maximum term of imprisonment or (notwithstanding section 3571) fined not more than one-half the maximum fine prescribed for the punishment of the principal, or both; or if the principal is punishable by life imprisonment or death, the accessory shall be imprisoned not more than 15 years."
http://www.law.cornell.edu/uscode/text/18/3