Mother Teresa was tapped by God Almighty the day she responded to his call for her to minister to the sick and dying in Calcutta.  People don't need man's approval for sainthood.  Only God can grant that honor.  I've read two of Mother Teresa's autobiographies and they're complex reflections about her God-given mission to humankind.  Remarkable woman in the eyes of God.  That's why he picked her for the task of cradling dying babies and people afflicted with leprosy.