Roughly 25% of ME/CFS patients suffer from Severe ME/CFS and they often require specialized care. For basic information on what Severe ME/CFS is, see this resource from the 25% ME Group.
Supporting someone with Severe ME is intended to help a carer or other people around you to understand many of the physical and cognitive difficulties faced by a person with ME/CFS, along with some of the causes of those problems. The authors also provide an easier-to-read downloadable introduction, as well as an article written for the nursing profession.
A severe ME patient wrote a book about living with severe ME and shares her experience on a blog called Surviving Severe ME. For a thorough documentation of information related to Severe ME, you can also try the MEpedia page.
And if you are currently bed-bound, you can connect with other bed-bound people in our Living Life from a Bed sub-forum.