These words are mine, in reply to your question: I'm sorry to know you've just lost your father. I wish, right now, that I could think up some words that I'd think might help; but having lost both of my parents (a long time ago), I don't really think there's anything I know of to say that would help. The only one, thing (thought), that helped me get through some of what surrounded losing my mother was to realize that, since by then I was a mother of teens, myself; I realized that if anything happened to me I would have been OK with it (for myself), and my biggest worry/concern would have been how they would deal with it. So, to me, if you can imagine how all most parents ever really care about is their child's/children's happiness and strength, maybe it could help in remembering that your father was always the parent, and you remained the child he wanted to be happy.
Other than that (and to be candid), I don't recall a whole lot about who said what to me immediately after each of my parents passed away. In early grief we tend to be numbed, so we get through those awful days however we do; and gradually, we start returning to feeling more like ourselves. So for me, it was just a big, awful, fog that I don't remember much of (at least once the burial was over). What I do recall (from each time I've ever been through losing someone close) is that I've found one idea in my head that helped give me something to hang onto - one thought that made it just a little more tolerable. Then, every time I'd start to slip into thinking up all the other kind of sad or awful thoughts, I'd remind myself of that one thought that helped me; and I'd just keep thinking of that in order to help me get through those particularly difficult moments.
Another thought I've always had (separate from the individual ones I had for each person's passing) has been that it can help to keep in mind that there are some things a person could go through that are worse than death, and - strange as it seems to find comfort in this - sometimes it helps to realize the person doesn't have to go through some of those "worse things".
Again, I'm so sorry to know what you're going through. You may wonder how you'll do it now, but you'll surprise yourself at some of the strength you find you can come up with.