The Bible is a human book. Each writer was addressing their own immediate community with the intention of affecting the behaviour of that community. It is therefore critical to understand what each piece of writing meant to that community at the time it was written -- their culture, concepts, understandings, idioms, the contemporary secular and religious politics, etc.
It also means that we are reading only one point of view, so some is propaganda. Few of the OT people could read, and even fewer could write. Most of the OT was written shortly before and during the neo-Babylonian Captivity.
The list of NT books was decided by the dominant section of the Church during the fourth century CE, in collusion with the Roman Emperors. The accepted list was first drawn up in the 4th century CE by the Trinitarian Athansius. Unfortunately, not only did they select writings that suited their viewpoint, but they made serious mistakes. Several of the accepted writings were written long after the supposed authors had died. As one example, Paul did not write 2 Timothy; another example are the writings wrongly attributed to Peter.
Then we have the numerous deliberate and accidental changes during centuries of editing. So much so, that it is impossible to know what was originally written. Consider also the differences between the MT and the LXX (Jeremiah, especially), as well as the differences between them and the DSS texts. There is no evidence that God bothered to protect the text.
I suggest that your friend distribute printed copies of his speech at the start of his presentation.
Doug