The late, saintly Fr. Hardon was my initial mentor when I became a Catholic. He received me into the Church, received my wife Judy back into it, and sacramentalized our marriage in February 1991 (see photograph below). He also baptized my first two boys, Paul and Michael, and wrote the Foreword to my book, A Biblical Defense of Catholicism. I have a web page about him (that I badly need to update!). I studied with him for several months during 1990-1992 or so, as an informal member of his group of "Ignatian Catechists": at the University of Detroit. I shall never forget the great privilege.
May he rest in peace. Fr. Hardon was a close advisor to Servant of God Pope Paul VI, catechist for Blessed Mother Teresa's Missionaries of Charity (see many photographs with Mother Teresa), and one of the leading catechists in the world. See the website for his cause (possible eventual sainthood) -- also the Facebook wing --, a great video about him below, and article on his cause by James Maldonado Berry, as well as other similar articles (one / two / three / four / five / six / seven).
Servant of God - Fr. John Hardon, S.J. from St. Louis Review on Vimeo.