The fruit that is commonly called "Pawpaw" in South Africa and some other countries is this one:

https://en.wikipedia.org/wiki/Papaya "The papaya or pawpaw is the plant species Carica papaya"

From the photos, the author is however talking about

https://en.wikipedia.org/wiki/Asimina_triloba "Asimina triloba, the American papaw, pawpaw, paw paw, or paw-paw"

Which doesn't appear to be closely related at all. They're in different Orders: Magnoliales vs Brassicales