I'm sorry to hear about your dad's passing, and I know you wish you could have said goodbye first. But the important thing is that the two of you had a great father/son relationship, so you shouldn't feel the need for any regrets.
I don't know if there's life beyond death, or some kind of superior/supreme being(s) watching over us, but I choose to think that there is (on both accounts). There are too many strange things in this universe for me to believe that mind/spirit is nothing more than the product of electro-chemical processes taking place within a material body.
I'm going to be facing this scenario with my own father and mother before too long. It's scary to think about, because it reminds me that I'm a lot older than I prefer to think of myself as being (in my mind I'm still a teenager), and I don't want to admit to myself that my time on this planet grows shorter with each passing year. I've lost friends through the years, but the death that had the greatest impact on me so far was when my younger brother died from internal injuries sustained in an automobile accident a few months after I graduated from high school. I saw him in my dreams afterward-- and still do, occasionally. I'm sure most of them were/are just dreams, but there was one in particular that stuck in my mind:
I met my brother at a large outdoor festival-- there were some buildings like a small town, or the streets of small buildings and shops you see in Disneyworld and the like, plus large open areas where people could address the crowd or put on shows. As I understood it, it was a kind of fair or festival that was put on by the "dead" so the "living" could mingle with them and hear about their experiences.
I distinctly remember that at one of the outdoor areas or booths there was a man giving away free packs of cigarettes to anyone who wanted them (and many people accepted them), because he said he'd had to give them up after having both of his lungs removed due to lung disease caused by smoking. (I'm a smoker, by the way, albeit not a heavy smoker.)
And my younger brother told me he'd been writing poetry-- I got the impression it was part of his "adjustment process" in some way. He read me one of his poems, which I still (mostly) remember. It was very short, and not at all like the usual idea of a poem:
"What do we call the one who put the oak the way it is beneath the pine?" asked the owl.
"The Devil," said the rabbit (or some other animal?).
I don't pretend that the dream was "real"-- I don't know if it was or wasn't-- but I do remember it all these years later, and I've often thought about the "poem" my brother read to me, because it was so odd. The best "sense" I've been able to make of it is that it was about things positioned in a less-than-ideal environment or situation, like a seed that falls on a granite outcropping rather than in loamy earth. (I assume that pine needles shed by a pine tree must do something to the acidity or alkalinity of the soil which might hinder the "ideal" growth of an oak sapling, or something like that.) And the answer to the owl's question-- as well as the wording of the question itself-- was also intriguing. The question wasn't "Who is the one," but "What do we call the one"-- which suggests that the answer may be more a matter of perception than reality. And then there's the fact that the question was posed by the (wise) owl but the answer came from a meek (and possibly not-so-wise) creature, like a Zen master asking a riddle to assess a student's understanding as exhibited by the answer given.
I didn't mean to go off on some bizarre tangent-- although I'm known to do that sort of thing-- or to forget about your advice about saying "Thank you" and "I love you" to our parents or other family members and friends before it's too late.
I guess what I want to say is that-- whether or not you believe in life beyond death-- you should take a moment to say goodbye to your departed father, to thank him one last time, and to wish him well on the next phase of his journey through the mysteries of existence. You never know-- he may be listening and watching from the other side.