I heard recently (Izkor Shemini Atzeres) from our Rabbi that we invite during Izkor the Neshamot (souls) of our parents and grandparents and other dear ones to come join us and share the Yom Tov with us. I honestly think it is a very weird and bizarre idea to say the least. Before I challenge him, since he is a Talmid Chacham I would like to know your open minded opinion if there is a chance he is right. Is there?
A. Horav Shlomo Miller Shlit'a in principle did agree with you. However, the fact is we do invite during Sukkos the Ushppizin (souls of the Seven Fathers of our Nation) to join us. Some even have the minhag to set an empty chair for them to sit in the Sukka.
It reminds us of Kisso Shel Eliahu Hanavi, or the chair set in every Bris Milah for Eliahu Hanavi to join us and also sit with us, or the cup of wine we prepare for him to drink during the Seder of Pesach, when we open the door for him to enter and share with us.
There are many reliable stories of people who were actually saved by long gone Tzadikim that came to their rescue and gave them the right advise or help in times of great need.
Searching further, I encountered a similar idea in the Drashos El Ami (1: 23) by Horav Amiel zt'l, (Rav Harashi of Tel Aviv - Yafo) that we do invite the long gone souls to be with us during Izkor.