Probably they are sick fucks if they are trying to make some extra coin off their daughter selling videos -- but there doesn't seem to be any proof of that.
To take the other side -- this is a 12 year old girl starting puberty... if a young adolescent is curious about his or her body/sensuality/etc... what could be more natural, comfortable and safe for a young girl than to learn from her mother... Our society may think this is child abuse but as long as it was the daughter's idea and there's no proof that any videos were sold it all sounds harmless to me. Every kid in the world is going to want to play dress-up to be like mom or dad -- and how many little girls want to be models? Modeling school for young girls is a huge biz. My girlfriend's little sister used to go to this modeling school and she loved it:
http://www.modelingschools.com/ (Barbizon) These 4 kids are going to lose both of their parents.... Really it's a sad story.