From what I have gathered, government and non-profit accounting is generally the most laid-back as far as schedule, stress, and demands, so I would think seriously about those options.
Also try to be honest with yourself about how much this will affect your work and how much your boss can afford to have that much employee time affected. If it could potentially make you miss a week without notice, especially during the most busy/stressful times of the year, then a 2-person accounting firm is *not* the place to be since 50% of the workforce is gone if you're gone. (I started in a 2-person firm, and the pressure to be there was a little high because I knew that me being gone meant we got 1/2 as much work done!) In my current work situation, I'm in private accounting and have 5 coworkers in my department, so you'd think that something which caused occasional unanticipated missing wouldn't be as big of a deal…but we also have a 3-day super-intense block of time each month during which any missing is very damaging to the team as a whole. We each have a single backup and if we missed during that time, our backup would basically have to put in our 12-hour days as well as their own (though honestly their backup would help them etc. so it wouldn't be 24-hour work days, but they'd definitely have to add a lot of hours). So, not a great situation for someone who honestly thinks they may end up out for a day or two during the highest stress time.
However, if the more likely option is that you might have to work different hours but you could still work, then you'd be OK in the above situations, but wouldn't be as good with something that required a lot of appointments or availability to clients during certain hours. In my current job, if I needed to work 7pm-7am for some reason, honestly, it wouldn't mess up much of anything. We work closely with a department in India that does the same thing we do for the Asian part of the business, and if I worked overnight, it would mean I wouldn't be in the office when our American contacts were but would be when our Indian counterparts were, so really would have some advantages. My boss wouldn't want me to do this regularly, but if I had a really good reason to do it sometimes, she'd probably just go “If you want to be up all night, that's up to you”. So, if you think that you might sometimes need to come to work more like 10am but you'd be happy to still stay till 10pm, then something without much client-facing time might work out fine for you, even in a higher-stress, tight-deadlines environment.
As for how to talk about it, presuming that it would be somewhat legally protected, I wouldn't make a big deal of it in interviews etc. I'd try to ask enough questions to know how much of an issue it is and let out enough information to find out how they'll react (because having a boss who hates the way you have to work is no fun at all) but not feel like I needed to spill my guts about everything.
This all comes from not being in your shoes myself, but having a boyfriend with issues that have a major impact on his ability to work and having a coworker with (mental) medical issues that have required some working-around in our department, and seeing what has and hasn't worked out as well with her. (Like, during our 3-day crunch time, there was one day that she didn't make it to work till 10 or 11…but she stayed late and made sure the work was caught up before she left, so it wasn't as big of an issue as it would've been otherwise. If she'd been unable to come in till late and then unable to work a full day, that would've been an issue because we can't afford the loss of workforce during that time and my boss would've had to explain that to her.)
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