These may just be details in a bigger picture, but can you stretch to some practical solutions, like a few extra bins (even cheap stuff from Wilkinsons), and some kind of basket beside the wardrobe/bed/wherever he tends to put the hangers? Can he try and scoot the shoes into a corner or under the bed if he needs to take them off there and then?
There's also an issue of different levels of mess / tidiness tolerance here, as well as the pain making it difficult for him to keep to previous? your? standards.
Can he just be messy in certain corners, say beside a favourite chair or something, so it doesn't spread everywhere? Compromise on 'zones'?
Would he be able to clear stuff up later himself, whether it's in a few hours or a few days, if he has fluctuating levels of illness?
Although if someone is in that much pain/ is that tired, doing things you're unmotivated to do can be incredibly wearing in a way that a lot of people just can't make sense of. If you are naturally neat but tired and ill, it's easier to use phases of feeling better for something like that without resenting the use of fleeting okayness on it.
Presumably he's checked if he can get better pain relief?
You both sound fed up and like you could do with feeling looked after. Don't suppose it's possible to afford a cleaner, even once a month?
Or are there any friends or relatives who might be able to help out occaionally?