"It also falls prey to a reductionist view of Christ Himself presented in the Gospels as "a man" working "signs and wonders" but whose divinity is the result of later writers' "re-interpretation." Ambiguity also surrounded Kasper's treatment of Christ's claim to be the Son of God with the Resurrection and Ascension being questionable historical events. True, "Jesus the Christ" is affirmed, but not without some equivocations that obscure the Gospel writers' simple faith that Jesus is God."  
There are numerous articles on the Internet regarding this issue.   Try reading his books.  
If a Cardinal in the Catholic Church questions the Transfiguration, The Resurrection, The Ascension, and the numerous miracles detailed in the Bible as myth, not fact,  I think a judgement of apostasy is right on the mark.