Who knows what really went on? A "documentary" like this can be completely slanted to serve a specific POV.

If the abuse really was as represented it would be hard not to have a lot of sympathy for the brothers. My guess is that they really magnified any abuse to make themselves sympathetic figures,

Seems like the father was a bad person in any event.

I wasn't really persuaded that the brothers were particularly sympathetic figures. Not sure that going out on a wild and reckless spending spree immediately after killing their parents (undisputed) indicates a lot of remorse on their part.