Heidegger's theological trajectory is perplexing.
"He went from being a devout Catholic to a generic Christian with a strong interest in Luther, to a scholar interested in pre-Christian paganism [Nietzsche], then to someone with an interest in something akin to Buddhism or what John D. Caputo describes as 'a meditative, silent world reverencing' and finally he asked to be buried with the full rites of the Catholic Church. 95
"Heidegger abandoned his Catholic faith in 1919 and in the 1920s turned to Protestantism, particularly to Martin Luther's criticism of scholastic metaphysics...
"...What interested the young Heidegger was...what he called the 'hermeneutics of facticity in concrete life' or being as it is in time, which became known as an 'existential analytic' in Being and Time. The key categories of this analytic were care and existence, concern and instrumentality, temporality and historicity.
"In the 1920s these categories were appropriated by Rudolf Bultmann, one of Heidegger's collegues in Marburg, and applied to his deconstruction and demythologization of the Gospels.
"[I]n the 1930s, Heidegger's attention was drawn away from Luther to the works of Friedrich Nietzsche (1844-1900) and the poet Friedrich Hölderin (1770-1843)." 94
From Chapter 5: "History and Ontology after Heidegger"
Benedict XVI: A Guide for the Perplexed, Tracey Rowland, New York: T & T Clark, 2010.