My grandfather died

Hey, thanks for reading :) I did a little research on what the symbols mean but it didn't make sense so that's why I'm asking here :)

Just a little bit of context: my grandfather who is now 81 underwent a surgery because he had cancer. He is well now. We are pretty close but I don't visit often, maybe once every ~10 days. He doesn't represent a major role in my life but he does mean a lot to me. And something about me. I'm 16 and I'm terrified of death, my own and of people that are close to me. I don't believe in Heaven, reincarnation, or everything of the sort. What saddens me the most is the fact that people who died are going to miss so much. Especially the world-advancement things.

And in my dream, he died. I don't know why. Outside the house where he lives, there were a lot of people in black walking towards the gates. They were carrying his coffin and I suppose he was in it. I wasn't among them, I was on the balcony where I could see all of them. There were some people with me and I don't remember who but something in my gut tells me it was my brother, father, mother (the daughter) and my grandma (they are the most important people in my life). And then, on the other side of the balcony fence, there was my grandfather, he was levitating or something. We weren't shocked by his presence. It was like he came to say goodbye. He reached out for my hand, as this is the way we always greet. I took his hand and hugged him, started crying and told him:"Sorry I wasn't a good grandson." Then I went downstairs, crying. I stood at the bottom of the stairs and my cousin who I'm not very close with was looking at me. When I noticed she was looking at me, I started crying even more and rushed upstairs.
Then there was another part of the dream. I suppose a long period of time has passed because my family seemed very normal but I couldn't stop crying. My parents were watching TV and they were laughing but not too hard, normally. I remember this was at an unknown place which is kind of interesting to me because the "first part" happened at a very specific place (where my grandparents live) and this was in some dark, rustic house which doesn't appeal to me at all.

The "I'm sorry I wasn't a good grandson" part, I suppose that's the not-visiting part because, other than that, I consider myself a good grandson. But the other parts aren't clear to me.

Thank you and it's really nice to be here :)

Edit: I forgot to add that he wasn't well after he had had the surgery and during that period I had a lucid dream. I was completely aware that I am dreaming. My brother and I were at home and the phone rang. It was my grandma, she was crying and as soon as I heard her crying, it was an instant change of my facial expression and I said "No". She then said "He's dead" with such a sad voice, it haunts me to this day. This was about a month ago. After that, I stopped dreaming.

I am very sorry that you have to experience your grandfather's death in your dreams like that. I really don't think that this dream has to mean much more beyond what you already know: you are terrified of death, you fear that your grandfather is going to die, you think you will not take the grief well and you fear you will have regrets over not visiting him often enough. I think that's what this dream is about.

Oh, and sometimes our dreams present us with places we don't know well. Often houses are interpretted to represent the dreamer's mind, so your dreaming that you find yourself in an unknown house maybe is about how you expect that when the time comes when your grandfather will die someday, you expect that this will be an unknown situation for you, that it will change your outlook, that you will not be yourself with grief perhaps. And I think maybe you expect your family to handle that grief better than you will when the time comes.

Something to keep in mind is that it is very unlikely that this dream means that your grandfather is about to die. Yes, he is old, and yes he had surgery, but you think he is better now, and hopefully he will be with you for a while still. However, we all must die eventually, that is part of life. Your grandfather is old enough that this is a very real worry of course that this might happen sooner than later - however it could very well be that the sooner is years from now, you do not know that (unless the doctor has given him a short life expectancy, there is no reason to worry otherwise). There is no point in grieving your grandfather in advance. It will not help him or you in any way. You will have time to deal with the grief when the time comes, but not sooner. What you can do now of course is to try to visit him more often if possible. If not possible, if he lives too far away and you cannot get there, then do the best you can, and there is no point in beating yourself up mentally over something if you cannot make it better, but if you can improve it, I am sure your grandfather will appreciate more frequent visits.

Also, you were probably preparing to say goodybe to your grandfather.
And you saw that you weren't close to your cousin, similar to with your grandfather, which made you sad so you wanted to rush to aspire against that.

Later, you couldn't stop being sad about the thought of people dying, maybe while everyone else was happy, or your better-knowing side knew you could be happy. Maybe it was mocking to you. So you felt stange and unknown, which you didn't like at all.

LUCID DREAM:
Because he wasn't well, you feared his death for real. But in you knew it was a dream.

Sometimes we have "obvious" dreams. If we are unhappily in love we may dream the person we love, is in love with us, or rejects us -- fulfill our dream or repeat our bitter experience; or if we have problem with money we will dream that we have lots of money, or that we cannot do this or that because we have no money; or if we were abused by someone in our childhood, we may dream that we are abused by that person when we are grown ups. Or if we are afraid of death and very troubled with the fact that everyone will die and so forth, then this dilemma will turn up in our dream.

One could call these "obvious" dreams -- it feels obvious why we have them, and often one can dismiss them because they do not add anything we didn't know. But if one would like to try to interpret these dreams, one should keep an eye out for that which is not obvious in the dream -- because that is what the dream adds, and there is almost always something unexpected in these dreams.

For instance, if I'm in love with somebody who isn't in love with me I dream that we are happily together -- an obvious fantasy. But what I don't think about, is that the setting for the dream is my childhood home, where the object for my love has never been. So that adds something to the dream, and I can learn something about my longing for this person by pulling that thread: Why in my childhood home? -- Or the person who abused me when I was a child is violent and threatening in my dream, well that's obvious. But on closer inspection we notice that he is threatening the dreamer with a butter knife, which is a totally harmless tool. That is not obvious, that is something the dream adds which symbolize something I was not aware of. So if I want to understand this dream, the butter knife is the key.

One should always note that which is unexpected, out of the ordinary, or to put it in another way: Out of the reach of the consciousness. That is what the dream, a spontaneous reaction from the unconsciousness, adds.

So in this dream, if you want to interpret it, you need to keep an eye out for that which is not obvious, and that might be your cousin. Who is she, what is your relation to you, what does she symbolize, and why is she found below -- and why did she make you cry even more, and why did you run away? That scene is the key to the dream, the cousin is a symbol for something you are unaware of in an otherwise conscious setting.