The belief system behind Steiner is that illnesses and disabilities are blessings (okay - quite positive perhaps) because they are a way of aligning our karma where it has been derailed in past lives, and that the disability and illness is an expression of that and needs to be accepted, and endured, in order to reach equlibrium.
Now this CAN mean accepting disability and illness as a part of the community, but it can also mean ignoring any duty to support the child if that support takes away their ability to 'endure it'. iyswim.
It really depends on how far the particular school has taken on the belief system.
Children with disabilities often don't fit into the formal education system we have in the UK, so Steiner, where they can at least appear to be allowed to be themselves can seem attractive. The trouble is that many disabilities require intense and explicit instruction and regular practice in deficit areas in order for the child to learn the skills required to participate in society as adults. The steiner system doesn't allow for this.
fwiw my neice attends a steiner school so I know quite a bit about it. It is fine for her. I wouldn't say great, but fine, and she really enjoys the gnomes stuff.
It would be terrible for my ds.