It's in there...There's nothing expert about it...It's all basic stuff...
Trust your own eyes and ask God to confirm what you see...
2) There is sin that does not kill the soul.
3) Jesus went to the souls in Prison. we know that his was neither heaven nor Hell. Clearly a third state. You want to call it the bosom of Abraham, great knock yourself out. What ever you call it, it was clearly a third state.
4) We know that Moses and Elijah both appeared and were visible to the Apostles on the mount of Transfiguration.
5) From the Story of Lazarus (The beggar) and the rich man, we know that there is a gulf that no human can cross.
6) we also know from the Book of Maccabees that the Jews prayed and made offerings for the dead. Now I know that you don't believe that this is an inspired work, but from a historical perspective it does show the Jewish religious practice. Those in Heaven don't need the prayers, they are not efficacious for those in Hell. Clearly they are offered for those in the third state.