White Nationalist cult

[Daoguy]

Recently one of my old high school classmates started sharing videos by some online white nationalist cult leader with many people they knew including me. I think they are trying to get people to join this cult and spread their ideology. The cult has similar characteristics that Leo described in his video. It has a hierarchical structure with a charismatic leader and several lieutenants who are trying to change society to match their ideology. They are trying to brainwash people by making them use certain words and negatively describe anyone who disagrees with them as "antiwhite". 

How can I help this person leave this cult? 

Their weird intro video shows how strange they are: 

If any one has any ideas, advice, thoughts, etc. They would by appreciated.