to help me understand friend with chronic fatigue

Do you mean Chronic Fatigue Syndrome?

Maybe she thinks you understand because you have a disabled child and know what it's like to experience something that fundamentally changes your life day to day.

But what's worth remembering is that it's not just fatigue. Your friend will feel often like she has the flu too. This is the effect of doing whatever she's managing to do.

It also fluctuates which is soul destroying to live with. It's cruel how some days you can feel vaguely normal and then others like you want to die. Constantly being shown what you're missing out on and what life was like before illness.

It's also worth pointing out that you only see her on good days. Those times you're not with her, you don't know how she's feeling or living.

Echo a PP saying to watch Unrest on Netflix. It's an eye-opener.

If she's only just had to stop work she'll probably be having a bit of an inner crisis over who she is now, especially if she previously defined herself by her role or did a job with social prestige. If that's the case I'd recommend Alain De Bouttain Status Anxiety to her as she enters a new phase of her life.

It might be the only thing she has in her life right now.

I have a child with moderate CFS/ME (chronic fatigue) and she has zero energy for social life so she doesn’t have one. If she’s not in school, she is literally bed bound. Her school attendance is around 70% so she tries to keep up using a laptop in bed. Sometimes I have to bring her her food on a tray as just going downstairs to the kitchen leaves her with not enough energy to eat.

If your friend has CFS, it is very much on the very very mild end of the spectrum.

I’m a bit surprised that she has no energy to work, but plenty of energy to socialise. Normally CFS sufferers cut out the social stuff first and preserve their energy for school/work and daily self care.

So I feel YANBU in terms of questioning her priorities. She may have CFS and thus not enough energy to work and have a social life, but honestly, if she can do such a full and active social life that energy could equally be spent doing some part time work or getting accommodations for short shifts, rest breaks, homeworking etc.

She's going on about it because all of a sudden she's had a massive, massive change in her physical abilities and it's a huge shock to get used to. With CFS it's not tired as in normal tired, it's different level. Like describing labour pain as "painful" to people who've never felt worse than a paper cut.
Yanbu to not understand because you can't until you've experienced it yourself. Yabu to think she can shuttup about it though. I'd back off and give her space and time tbh.

Have you tried talking to her about how tough things are for you too? Some people are so focused on their own 'woe is me' they truly don't realise that other people struggle too. It might become more equitable if you can both have a moan. If it is that draining to spend time with her I would only do it if you have the energy and try to see other people socially that do not place such an emotional and mental burden if you are coping with so much yourself. I have a disabled husband and child and sometimes just need light and fluffy social time to escape, if she can't do that then maybe minimise contact if you have little reserve left otherwise you will burn out. It is not unkind to set limits in the interest of self preservation.

There's a great documentary on Netflix called Unrest, which you would find useful and enlightening.

Have a look at the spoon theory- helps me understand friend with cf.

Did she self diagnose?