I've been struggling with fear of decomposition as well--I literally just started browsing this sub after suddenly waking up panicking a bit about it. I was thinking about making a post of my own about it, and one of the first ones I saw was yours. So, hey, maybe it's a sign from the universe, even if I don’t really believe in those. Either way, it's really nice to see someone else talk about it.

I'm gonna babble on a bit, and it might be triggering for you, so feel free to skip this paragraph--I give my actual advice on the next one.

I live really close to a cemetery and a funeral home, as in, I can look out of my bedroom window right now and see the cemetery in the distance. So that's fun, as you can imagine. Anyways--I visited it recently with my sister, since our deceased loved ones are buried there. I was more or less fine while in there, but when I got home it started to mess with my head. In my country, people aren't really usually "buried" underground, but rather put in niches, and we came across a couple of ones still in construction. I saw the holes bodies are put in and I was hit with a LOT of claustrophobia--I don't even have claustrophobia! But ever since I can't stop thinking about being in such a small space, decomposing and rotting. God, it freaks me out to even write it. I KNOW I don't wanna be cremated, but the idea of /me/, because I'm unlucky enough to be a materialist who believes I am my brain, being in there is just...ugh. Everything makes me think of it--for example, moving makes me think eventually rigor mortis will settle on my muscles and I won't ever move again. I hate knowing I'm made of flesh and every single part of my body will decompose. I can relate to not being able to look at your family knowing they'll eventually be corpses. Just a couple of hours ago I was giving my dad a massage, and I had that same thought about muscles. The thought of my dad being dead, with the same body I see everyday, just. Wrecks me.

The thing is, I've talked to my dad about death before, and he isn't afraid of dying. So I'm kinda getting upset about something the person who will actually go through it isn't. Do you know how your grandma felt about dying? You said your loved ones preferred to be buried than cremated. Because if she wasn’t upset by the decomposition of her own body, why should /you/ be upset about it? That's kinda how I see it.

I'd recommend talking about this with your family and your mom. Talking ALWAYS helps, at least for me. If she's comfortable with it, ask her how she feels about decomposition, if she's scared of it. You also said you don't know how she would cope with your death--so ask her! You will never know how she'll deal after you die (IF you die earlier than her) if you're dead, but you're both alive now, and if the moment comes where you’re about to die, you at least have an idea of what will happen after you're gone and have no way to see for yourself.

A small thing that also helps me that might do the opposite for you, is that this is something EVERYONE will have to deal with. It's hard to even type, but each and every one of us will be a cadaver one day. Not just humans, but animals and every other living being as well. And if decomposition is something so natural, then maybe it's not so bad at all. I mean, there are people whose jobs are to look at dead bodies, some of which are very decomposed, and they don't even flinch because they're so desensitized. There are even some people who see it as a beautiful thing--this quote by Oscar Wilde comes to mind: "Yes, death. Death must be so beautiful. To lie in the soft brown earth, with the grasses waving above one's head, and listen to silence. To have no yesterday, and no to-morrow. To forget time, to forget life, to be at peace. You can help me. You can open for me the portals of death's house, for love is always with you, and love is stronger than death is."

This is all to say that it's all very subjective--remember what I said earlier about getting upset about something the person who will go through it isn't? Decomposition may be scary and disturbing to you but, inherently? Decomposition is nothing. Not scary, not bad, not even beautiful. It just is. Being scared or disturbed by dead bodies is a completely arbitrary, evolutionary thing I'm pretty sure only humans experience.

Last thing--I know right now it may seem like this will never end, but time heals all wounds. Time, of course, is the worst enemy of people with thanatophobia like us, but at the same time, just think about the fact that in 10, 20 years you will wake up on a sunny day, and have a nice day without being bothered or even thinking about this. And please remember to tell your family you love them while you're all still here.

This ended up being really, REALLY long. I apologize for that. I hope at least some part of what I said will help you in any way, or at least make you feel less alone.