Please point them out.
Basically, his whole position is flawed. Contradictory to both scripture and history. As I get time I will point out some specifics---but generally:
"Sola scriptura" as a doctrine is contradictory to scripture itself, which is VERY clear on the subject. I don't see how Paul's exhortation can be any clearer on the subject.
Also contradictory to history, as there WAS no "scriptura" until very late in the first century, as none of the Gospels had been written---ALL teaching(s) of the church up until that time were oral (i.e. "tradition"), and even after that, the vast majority of Church teachings were not set down in written form until centuries later.
In fact, the "canon" of Scripture STILL is not complete (as we know from internal evidence of existing Scriptures that there were some writings of the apostles that have been lost).
Yet when we further examine the continuing history through later verified writings of non-Apostle (but still "apostolic") writers like Clement, Ignatius, Polycarp and others, we find an unbroken continuum of teachings OUTSIDE scripture that has held constant from the first utterings of the Church up to the present time.