That was perhaps the most cruel letter I've ever read. Bruce Springsteen said (although Johnny Cash's version is better)
"If a man turns his back on his family, he ain't no good"
Its amazing how people who are considered "spiritual" are the most cocky, condescending know it alls you could ever meet. Its hard, but be the better person. Karma is a funny thing (if I believed in that sort of thing)