In keeping with the thread's theme, both a response to the OP and 'relationship-affecting':
Response to the OP:
Since my brother and sister live 2 hours away, I am her main support person when she needs rides to doctors, help around the house, and I manage all her administrative needs, finances, taxes, etc.
We are now working with an attorney to create a new will and trust. When it came down to answering how she wanted assets distributed she wants me to be the executor of the estate and she wants all the assets put into a trust for my younger brother who is a nice guy but also a never-do-well who can't hold a job.
This is a situation I can personally somewhat relate to (taking care of someone 100x more than anyone else in the family, yet not really ever having that acknowledged). I imagine the most frustrating thing OP is going through is that the very person who is selflessly helping to take care of mom, taking time to take her to the doctor, watch over her investments, taxes, etc. is the ONLY one who is completely disinherited in all ways!
OP didn't retire early for the sole purpose of being mom's slave. For OP to take all of that time, effort, and concern is quite admirable (and some of these things you can do from a distance, if one of the other siblings ever cared to help out).
And it's likely the root of the feelings: why should OP go out of their way to do all of this with their FIRE freedom, when siblings don't appear to offer anything in the way of any help or concern or care? (just a guess, given lack of any details in the OP)
And as another poster noted, I surely would not want anything to do with being an executor or trustee of financial assets that ONLY benefit someone else at my 'expense' of being disinherited - not only from the likely headaches of challenges and arguments and distrust, but also purely from the continued self-sacrificial slaving away for someone else's complete benefit at your expense and effort.
Now, if it was a dear friend who asked me to be a trustee for their estate and their family because they knew no one and had reason to trust me and my knowledge, and I didn't have any familial relationships, then I would view it differently.
But I would simply start to help mom understand that you are going out of your way to be there for her, unlike her other siblings (unless they have done heroic actions for her in the past), and simply say that you are unable to fulfill her wishes as an executor/trustee, and simply recommend that she hire a service (perhaps Vanguard) for her estate and trustee needs. And then have her start going to H&R Block or a local CPA for her taxes next year - yet another item that you shouldn't feel compelled to take upon yourself. You are already doing volumes of great deeds for your mother.
You can still oversee everything and review everything - but don't feel compelled to continue to take on everything yourself.
"Relationship-affecting situation"
While other posters have commented on end-of-life issues, mine is more at the other end: while approaching FIRE in the not-too-distant future (hopefully!), I'm still dating and trying to find "the one". There have been a few other posts over the years about single members of the forum and their challenges to keep a low profile and protect themselves, while also finding someone that has a variety of characteristics.
I've only vaguely referenced the concept of possibly pursing early retirement "with my wife, if we're willing to really sacrifice and push for it" a handful of times to a few women I've dated. Once was a big mistake (but I already had started to develop a wonder about whether she was just 'bad news', and part of the reason for bringing up ER was to help flesh out a few more indicators that helped me realize she was truly mentally unstable).
Usually, I would only bring up the vague concept of ER either if she mentions retirement dates or ages first, or if things were that far enough along that I knew her spending/saving habits fairly well, and wanted to bring up a discussion about retirement).
Otherwise, I use a variety of indicators to both observe and indirectly ascertain what her spending/lifestyle habits and attitudes are like, since at least somewhat similar fiscal attitudes is one of the main important criteria I'm looking for.