Not sure, but maybe he is desperately trying to create some stability to feel secure, hence not wanting a change in your hair style, screaming for bedtime story, these are probably things he associates with how his life was before feeling so poorly. It must be so hard for him to make sense of it all.
It does make it incredibly hard for you as well, trying to do the right things but possibly almost impossible to please him given how poorly he is feeling.
It makes it even more difficult that nobody knows how long this stage is going to last, otherwise you could make a chart together and cross of the days, but of course in this case that is not possible as nobody can say when he will start feeling better.
My dd when very poorly loved to have me stroke her face, very gently around her eyes, tracing her eyebrows, along her cheeks, moving from her ear lobes to her neck, etc., very very softly and slowly. She liked that for hours on end, it calmed her down a lot. Not sure if it is something Joe would enjoy or not.
I suppose it is a small chance you will both get much sleep if the diarrhoea is setting in
, still hope you both will manage to get some rest.