What these two "women" (and I use the term loosely) did is unconscionable. But what you are recommending is punishing the child for the sins of the parent. These kids had no say in how they were born or conceived. It's not their fault that they are deaf. To deny them any services that other similar children would get only because they had "normal" parents is just plain wrong and misses the point.
A better response would be to have Child Protective Services come in and rule the mothers unfit and take the children away. Any legal action that can be taken against the mothers should be taken. But I doubt there's anything on the books to cover something like this.
Yes, but that's not likely going to happen. It's probably legal to do what those women did. By making these two women pay their own way is not hurting the children. No one is asking the children be denied services, just that these women pay for it themselves.