A Friends Sites he bought a few months ago tanked, his site all of a sudden deindexed. He has this message on his search console " duplicate submitted url not selected as canonical". I went and used copyscape and siteliner and noticed that he had duplicate content at 20-50% on some similar pages for example copying instructions to different articles for similar articles on his own website (internal duplication). The quality of content also looks spun or it has horrible non native english, but it passed copyscape so I doubt its external duplicate content. I also saw that there were two versions listed on siteliner the www. and the non www. version. What do you think is the main issue and what can I do reindex his site?