Donald woodman judy chicago harrassment

Recently a copy of New Mexico artist Judy Chicago's Judaic book The Dinner Party came into the possession my cousin via a Santa Fe estate sale. This book contains a somewhat strange lengthy handwritten inscription which appears to have been written by Judy Chicago. My cousin listed this book on eBay initially for $5000.00 and stated in his listing that he could not guarantee its authenticity--he also offered a 100% money back guarantee if the inscription with it's references to Jesse Helms and to Judy Chicago's work as being "pornographic" should it prove to be a fake. A party claiming to be Donald Woodman then contacted my cousin and attempted to intimidate him into removing the item from eBay. My cousin relisted the item for $1500.00 which was later removed by eBay--most likely due to complaints by the extremely arrogant party claiming to be Donald Woodman, "distinguished photographer". What is all the loud protest about? Subsequent to the listing removal my cousin was recently in downtown Santa Fe and noticed that a man appeared to be following him. This man later up with my cousin and then advised my cousin that he was a close friend of Donald Woodman and Judy Chicago and that if my cousin did not deliver aforesaid book to a certain party in Santa Fe within 72 hours he would quote "break his arm for starters." My cousin is now quite concerned and will not go out after dark. He feels that the alleged Donald Woodman interference with the book listing on eBay is a case of interference in interstate commerce--otherwise known as racketeering and that for some strange reason Donald Woodman is apparently using strong arm tactics to suppress and or destroy this book. Please help. What should we do? Is this the work of the Art Mafia?