I have asked about reconstructing pre-PIE from PIE and possibly using daughter languages for help and got no response. What I remembered is a book about Proto-Afroasiatic that I stumbled upon. First, I want to know what type of method the author used or may have used to create Pre-Proto-Semitic so I can recreate Pre-PIE and Pre-PU. To clarify, what I am asking is what the established linguistic method to reconstruct pre-proto languages is.
Note: Despite the fact that this branch only has two daughter branches, I believe that it was spoken approximately 10,000 years ago. Proto-Afroasiatic, according to Wikipedia was spoken twelve to eighteen thousand years ago. This is something that I might do later work on in the future if my future research finds enough backing for it.
https://books.google.com/books/about/Reconstructing_Proto_Afroasiatic_Proto_A.html?id=cN9yUe3AgQIC&printsec=frontcover&source=kp_read_button#v=onepage&q&f=false (Reconstructing Proto-Afroasiatic by Christopher Ehret, see appendix 1)