With respect to the former, Ratzinger takes a believer's approach to being and existence but seems to studiously avoid questions such as the preexistence of the soul, the nature of reality, the concept of something being uncreated but always existent, etc.

With respect to the latter, the Catholic Church has righted course and is now generally in agreement with science with respect to the way the universe was created and is continually expanding. The only distinction is that the Church sees a divine plan that set everything in motion (i.e., "Let there be light" in broader terms) and continues to be active to this day. As such, I don't think Ratzinger feels much of a need to discuss it.

He's not a philosopher, after all. He's a theologian working within a set of beliefs where much of the philosophy has already been resolved.