It's a brutal time you're going trough right now and I feel you and understand , personally , a lot!
You have to think rationally as well not just emotionaly , Its hard to control and understand the emotions and thoughts you're going trough right now.
The person I loved the most died in a very unexpected and random time, just one a blink of a eye, when you were thinking it might be longer , life hits.
Not many had a Father , remember that, I hope you had a good relationship with yours and now you got to take farewall and he will look upon you from the above , you have to live your life now brother, also ask Father Satan , do the incantation while focusing on His sigil, talk to Him, when my loved one died I asked for strenght to be strong enough so I could manage to go trough that moment , as you re doing now.
Father Satan helps the ones we loved, even if they are not ss, for as long as they are not against Him and the God's . They undestand the difference between a person which is unaware and one who does things with intent.
Have faith in the God's and dont worry about your dad's soul, he will be fine. I am truly sorry to hear your going this rough time but its inevitable , please stay strong and meditate and in time, you will re-see the loved ones.
When my loved one died , I could still talk to Him, even after months and even years.
Once I was in this dream with my loved one who died and he was asking me how's things in my familiy and how is everyone doing, I was telling him and then he laughed saying : ha! Tyipcal
So while chating then all of the sudden some black gray clouds come in a very fast and scary way , destroying everything behind them, wiping out the entire "space" that there was, while the apocaliptic scene was coming my loved one looked at me and said; It is now my time to go, you have long to live and many things to discover and do, take care of yourself, I love you, farewell! And that was my last ever time and now its gone eniterly , at least for now. I have the strong feeling that he was fine all of this time. Father Satan is the Greatest!