Unless you have experienced an 'invisible disease/disability' it is too hard to imagine. It is nothing like you could ever expect, comprehend or vaguely imagine no matter how hard you try. Truly, I never want anyone to have too ever do so! All one who has this can ask is for others to be patient, very forgiving, and be unexpectedly helpful. That is the best you can do for us, and ohhh yes! Do not get into a pissing match about 'how bad your feeling' vs how bad we feel all the time. Your cold/bad day etc goes away - ours often lasts weeks, months or years! Sure we have sympathy for you - trust me we can understand feeling ill/bad. But we have a really hard time keeping our own strength up, either physically and or mentally, to try to boost yours as well. I know this may sound rude - but it is only meant to remind those who are in our lives that we are trying and that (trying) can sometimes take all we have in us.
What do I mean when I say 'Unexpectantly helpfull'?
It is just that - be helpful even when we have not asked for it. Do not ask us 'IF' we want help. Because knowing myself, usually I will say no. Who wants to ever ask for help? Who wants to be 'beholding' to someone else. I (personally) grew up with the mindset that if someone does something for you, you should return the favor... this is just not possible for us the majority of times. It can cause me a lot of turmoil inside and undue stress. Crazy I know, but that is just me and I am sure many others who dream about days gone by when they could 'Do' for themselves without any help. So, how could you be 'Unexpectantly helpfull' to someone who is disabled/ill? Send an unomonmus gift card for a cleaning service to come in, or car repair, or even a massage. (Trust me we never seem to have enough money to do so for ourselves. Or if we do have the money, who thinks about doing those extras for themself.) Stop by on your way home with dinner, remember we may not be up for visitors, so fain the 'I just am dropping this off and can't stay' routine. (We don't want to be rude either and sometimes just do not feel like visiting.)
Be a true friend: I have personally 'lost' friends because I go through months of not feeling well enough to visit, go out, or do things with others. I am reserving all my energy for my immediate family and being there for them. These friend have gotten offended by my continuing 'no thanks' to their invitations. They take it personally no matter how many times I have told them that it is 'really' me, not them. I had told them numerous times that it is my health, to no avail and they finally stopped being in my life.
Then there are the 'true' friends I have made over the years. The ones who when they do not see or hear from me call, email send a note, etc. They are the ones who know I have only enough energy much of the time to do for my own family. They may not fully comprehend my illness - but they understand I am always trying. These are the true friends in my life, and I thank God every day for them.