I have a friend whose three of her four children are on the spectrum in mild but varying degrees. All of her children participate in some type of "special" program - one is in speech therapy, one art, etc. She also works with them at home - they are all mainstreamed right now (they are all in 4th grade and under).
So my question is - if your SIL's children are on the spectrum, are they receiving any type of therapies, or programs? If the 11 year old is mainstreamed, but no one - like the school, even knows he is on the spectrum than she is not parenting like she should be. If none of her kids are participating in appropriate resources, that could be deemed neglact- in my mind it is neglect for not helping her kids.
I don't care if she is borderline and medicated, if the family knows that the kids are not being cared for in the proper manner, they need to step up. If she is that ill, that she cannot properly care for the children, the family needs to step up and in and assure that the children are cared for. I don't mean food, clothing, shelter - but to let an 11 year old, on the spectrum, suffer because he doesn't understand what is going on in his brain, what is causing him to struggle, and not ensure he receives the assistance he needs to be successful, is neglect. And is setting him up for a lifetime of self esteem problems and, frankly, failure.