I think I've posted this before, but I'm worried about this in what is hopefully my distant future.
My inlaws have about 5-25 years left to live. Really no way of knowing, I would not be shocked if they both pass within 5 years and I would not be shocked if they both live another 25 years. My wife has one sibling. This sibling is 34-36 (I forget), has been unemployed for approximately 1/2 of their adult life, and delusional. Not to get political, but sibling is a Trump Supporter through and through who blames EVERYTHING on the democrats despite having been on unemployment more than anyone I know. Has lived alone away from parents for a total of roughly 3 years in two separate stints since graduating from college. Somehow despite parents paying for just about everything, sibling is in debt way past his eyeballs.
Sibling is an expert in everything, despite not knowing anything. Seriously, you could have written the book on Random Topic, and this sibling will start talking like he knows everything about it and knows exactly what the problems are with it. It is fun to start the topic of conversation on something you know you know a lot about, just to see where it goes. For example, I started it on Harry Potter one time. Sibling went on a rant about how JK Rowling fucked up her investments and ruined her reputation by not letting Disney take over the franchise and Universal Studios fucked up the rides and on and on spewing BS like you wouldn't believe. Most of it is nonsensical, the rest could make sense as a theory IF it was uttered as "I personally think that XYZ happened, and this is what the result is/will be. Obviously I don't know all of the details, but from what I can tell I'm making this conclusion". But instead sibling preaches it like gospel. Huh, you'd think if sibling was such an expert in everything she'd/he'd have started a business and be a millionaire. The most infuriating thing about it is that sibling would be the worlds best car salesperson, no joke - personable, you don't realize how full of shit they are until you've spent enough time with them, good looking, a good closer... but they're so image conscious that they think being a car salesperson is below them.
Anyways, after that letting off steam... my in-laws to my knowledge have no will. Likely will not be necessary as I anticipate that medical care will eat through their entire estate, whatever there is of it. But my FIL had mentioned that he was going to leave the house and the boat and the cars 50/50 to my wife and her sibling. I said "Do not do that, you don't want to leave anything but cash to wife and sibling." Hopefully he'll have listened. The other thing? My wife NEEDS to be the executor of the estate. Sibling-in-law would mess it up. Unintentionally (he legitimately is a good person, and generous), but still does not have the aptitude to do it. If my wife isn't, I'm sure that Sibling-in-law will end up with everything and blow it all and somehow blame it on my wife (despite being a good person, sibling is an idiot). Frankly, it should be me as I can balance a check book, but I'm not having that argument.
I anticipate that once one of them dies, the other will need to be in an assisted living facility. What that means for my sibling-in-law who hasn't paid rent in years, I don't know. But we're not going to bail sibling out. Can't do it. Not our circus, not our monkeys. Happy to help out. Happy to help someone stand up. Not going to let them live an extravagant lifestyle though.
Compare this to my parents... They've got everything set up, probably will live for another 10-35 years, have named me the executor for financial stuff and sibling 1 the executor for health-related stuff, with sibling 2 the first backup for both. Dad has showed me all of his accounts, all of moms accounts, and the steps to take when it is necessary. They've been consolidating accounts to where it will be as easy as possible, the only potential question is their vacation property which I've recommended they sell before they pass - that decision will be many years down the road though.