I'm sorry for your loss. I have OCD, and it comes with the downside of this being on my mind frequently...but the upside is using that worry to not worry but prepare.
I cannot agree more with OP. I will also add, if your health declines, or you're of certain age, give away "things" (Items) while you're alive. My Uncle told me that when I was 14. When he was nearing his death of the C word, he made good on his own advice, by giving things he knew people valued, to my mother, his sister. While this didn't work out nearly as well as I think he'd have wanted, he had the chance to experience the act of giving. It was gift to give and a gift he grew to that point to enjoy.
Spoiler for a personal advise for passing on personal ideas and private matters: (Highlight or hover over the text to view)
I seriously recommend one clunky solution to all passwords and personal thoughts. A Hangman's switch. I'll be brief. It's a command prompt triggered by UNIX time. If you can afford--the TIME--to, learn and practice with hangman's switch on a PC. You can jailbreak other devices, but I advise against it. Even a $100 laptop (heck even a cheaper one, if you can find it) will serve well. In short, you can seed hangman's switches into other hangman's switches. This means you can check in, and delay point of origin that the UNIX time looks to. In the event your final seeding occurs, and this is when you trust you'll be deathly ill, in prison, lost memory, or passed on; it will open the final prompt. You can e-mail, or you can launch a program of something like a slideshow. If you learn this well enough, it also serves as a time capsule you can open (by accessing the hidden program through normal prompt) and see what was important to you X years ago, and how you've survived to see an update in order. Share this, while you're alive, if you can. It's very sentimental.
I worry about my OWN memory too, not just the memory others have of me. If I develop dementia, this is still useful, whereas a will wouldn't quite suit that.
Again, I'm so sorry for your loss. Especially when it was so sudden. I've had a heart attack once. I lived (obviously) but I was alone, except for my roommate sleeping a floor above me. MY only thought was a wordless flurry of concern, for my friends. Losing someone is rarely easy. Having it happen suddenly or seeing someone wither are non-fungible experiences. Each ineffably painful. Each affecting a survivor unique to them and whom they lost.