While I am on the topic of online sibling support, I found this wonderful blog:
How I wish I could write one about Bil. But I don't think that my husband, Bil's brother, would allow me to. He doesn't want to be involved with any kind of online support.
It can be very lonely being the in law of an adult with autism. So much uncharted territory, a mother in law who has her own expectations about what Bil's future will be but just assumes we are going to go along with it, and a whole lot of other family dynamics.
But I feel myself on the verge of a rant, so I will just say: if you are a sib, explore the Sibling Stories blog. You'll be glad you did.
I just wish there was a similar support group for in laws.