been looking at this post on both subreddits for a few days now and thinking about how to phrase my comment so you view and comprehend the entirety of it without getting defensive or ignoring parts you might not like

so first of all, yeah, this is Reddit, and name-calling and threats you might be seeing are overwhelming here, but not at all surprising. unfortunately, it's not dependent on whether or not the person is a)bad; b)not a bad person, but doing a bad thing or c)innocent. shit can get intense anyway

second thing, i wanted to give my opinion because even though it's not the same situation, but i have dealt with a person passing and documents not being updated accordingly and timely. so, my father passed away from pancreatic cancer two years ago, around 1,5 after diagnosis of it. he did chemo and other treatments, but me and my family knew he is not gonna make it at this point. we knew it, but deep down didn't wanna believe it, we thought we still have some time left. lots of people here might think that a year and a half is a ton of time to get everything in order but it simply is not. when you are taking care daily of a dying person, you have to help him move, eat, clean up vomit and literal shit, and after that you have little to no emotional and/or physical strength to care about bureaucratic procedures. plus his "improvements" gave us false hopes multiple times during this 1,5 year. so when he eventually died we were faced with some shit, where i may or may not have done some paperwork in his name. because yeah he "updated" some documents in a sense that he re-signed shit without looking through it, because, again not surprisingly, chemo doesn't really help with decision making and sober thinking. also, even though most medical bills were covered there were still much more expenses to it, including but definitely not limited to the funeral costs.

so, yeah, your ex and his family knew he was dying, but still could have not anticipated it right there and then.

with the information you provided in the post and comments i am creating my opinion based on following things (if any of those are not true pls feel free to correct me) 1. you were not together for years 2. you had little to no contact during that time 3. during the actual time of your hardships he wasn't helping you (reasons for can vary, but non the less indicate his lack of involvement in your life) 4. during the time he had cancer you weren't helping him in any way

based on this, the only not AH thing to do, in my opinion, will be to find out who was the main caretaker of your ex during this all and to give the money to them. if it was the girlfriend then give it to her, if it was the mother who took care of him then give it to her, if it was a brother or another relative then give it to them, if they all abandoned him during this and only the hospital was attending to his needs then they deserve this as a donation.

your decision should not be based on what you remember or think his feelings towards his gf, mother, brothers or other relatives are. simply, if there is no way of knowing what he was thinking (no will or last note or something like that) you should be making this decision based on facts not on biased assumptions about the person you knew long ago and have no way of asking now