The fact that Jesus lived upon this earth and did miracles is a proven fact. The fact that Jesus died on that torture stake is a proven fact. The fact that Jesus rose bodily from the grave is a proven fact. 500 believers saw the risen Christ at one time.
While I would like to believe that Jesus was the Messiah, died and rose from the grave, the Reverend's statement above does not "prove" anything. The scriptures indeed state that he died, rose from the grave and that it was witnessed by 500 people, but that in itself is not "proof" anymore than the men* who (supposedly) saw the golden plates that Joseph Smith supposedly received after getting a vision from the angel Moroni. The fact that these men verified and signed a statement that they saw it, does not mean it really happened (and I think we're probably all in agreement that there were no golden plates).
*The Eight Witnesses were one of the two groups of witnesses who signed a statement (reprinted in the Book of Mormon) stating that they had seen the golden plates which Joseph Smith, Jr. said was his source material for the book. The other prominent group of Book of Mormon witnesses who said they saw the plates are called the Three Witnesses.