@trendless No LC experience, but speaking from MEcfs:
b) I'm not really sure what counts are surface-y where you or the family member lives, so I'll just recommend having the thyroid checked and checking for a B12 vitamin shortage. At least over here, surprisingly many doctors don't check for B12 shortage because it's rare and it takes years to develop because there's a large storage in your body. But I've heard so many people with ME tell me about managing their shortage, that I think it's more common than is known.
My theory is that many people get ME/cfs after EBV, and EBV can also ruin the stomach over time. Maybe other viruses can do that too? Certain parts of the stomach are needed for creating intrinsic factor, which is essential for being able to absorb B12, so without IF you can't get enough of it through food or regular supplements. If B12 gets too low, one gets anemic and it just gets worse and worse, with nerve and brain damage etc. B12 injections or B12 supplements under the tongue solve at least that problem so easily, that it's always worth looking into.
Also it might be worth it to check some patients websites for people with ME/cfs, many contain a list of the most important things to check for in blood tests!
a) I think the unpleasant answer is lots of trial and error and learning over the span of months or years, unfortunately. And you're probably already aware of all the pacing guides. But some things I've adapted to:
Tracking my heart rate. I've found many guides that explain that you need to measure your resting heart rate and then always stay below that + a certain amount of beats or % added. This hasn't worked for me, it was simply impossible (maybe because of pots too). But I've found some numbers for me that predict things quite well. If I go over 140, good job I messed up, there's going to be consequences, possibly a crash. If I go over 130, better watch out and rest asap, maybe I can escape severe consequences. If I remain between 60-120 as much as possible, I'm doing okay.
Not just the immediate heartrate, but also the pattern of how quickly it rises has helped. If I do a very small task in my house, and my heart is 90-110, that's okay. But some days I start the small task and within a few minutes I'm already going near 130. It's a sign that I wasn't as rested or well off that day as I thought, and I need to rest and be careful. Over months I've come to expect certain heart values with certain activities and if the heart rate starts to differ from that, I quickly know: oh, oh! before going too far.
Heart rate variability seems to give way more predictable and accurate information to many ME-ers, but it's hard to measure with cheap and convenient equipment. I have a bracelet that measures it so-so with a measurement they call 'stress'. It gives me information about how heavy something was to do the day after mostly. Usually my graph has blue/green bars, but when I do something that was unexpectedly tough for my body, I spike in yellow/orange bars the day after, or sometimes even the night immediately after the activity.
I think there's value in body signs that aren't easily tracked with accurate measurements. It's a feeling you build over time. Noticing that your body feels very heavy, or that your muscles are cramped, or that nausea rises if fatigue is too bad, or your body temp is starting to get low, or that tremors are coming to your hands, general dizziness -it could be anything. Noticing these in time as a sign of pre-crashing/too fatigued, helps with making the consequences less dire. For example, when I feel my body gets too cold, I get a warm water bottle and wrap myself in blankets. I might feel silly doing that, but it prevents me from losing even more energy on keeping the body warm.
It might help to note down these kind of body functions at first, to start seeing a pattern, although they start to feel very familiar over the years.
Anyway, I won't spam you any more 😆 , but these were the things that I thought of immediately. I'll add some extra hashtags, maybe someone else has some more information?