There are Deities for this and one has been given by Veil. Hecate and Hel are two more.
You’ll want to start working on your clairs - clairvoyance, clairsentience, and clairaudience. There are plenty of exercises on the internet for them and it may take a while, but it is the most concrete way of having conversations.
Now, you need to realize that you may not have all three or they may be at different levels. They take work, but evocation can help unlock them. So, use links like these.
Simple English Demonic Evocation Guide - New Magician Help & Introductions - Become A Living God
Petition Bune, Hecate, or Hel to help make contact.
Use the simple evocation guide to call one of them forth and ask them to bring your dad.
You will have to work on your skills to be able to speak, hear, etc… Eventually, you won’t need to evoke one of the Goddesses and can call on your dad without them. But only if you do the work. This will take some time.
Hope it helps.