Courageous Parents Network was a big part of the inspiration for The B.L.A.I.R. Connection. It is a network of parents with very sick children. It can be helpful to read their stories, because it is a different perspective and shows that you are not alone as you struggle as a sibling.
Siblings with a Mission serves and supports siblings and families of individuals with special needs and developmental delays. It was created by Nathan Grant, whose twin suffers from MPS. It includes more blogs by siblings of kids who have special needs.
Founded in 1990, the Sibling Support Project was the first national program dedicated to the millions of brothers and sisters of people with special health, developmental, and mental health concerns. They’ve published books for and about brothers and sisters, hosted online groups for teen and adult siblings, and presented workshops on sibling issues internationally and in every state.
The Rainbow Trust is an organization which provides emotional and practical support for families who have a child with a life threatening or terminal illness.
This is their section on sibling support:
Here are some of my favorite articles written about/by siblings of terminally ill children:
NY Times article about Rivers Schwenn, and her journey watching her younger sister go through Cancer.
An article by Sydney Weit, whose brother passed away from Cancer.
This Huffington Post article explains the stages of grief and how it changes the way your family lives and thinks.
An article from Rainbow Trust, mentioned above, about how to cope with a sibling’s illness.