I can see two sides of this.
On one hand, what she said is unacceptable. The way she phrased it is unacceptable.
On the other hand, as an administrator who has made the difficult decision to suspend children, including children with disabilities, I make that decision based on 3 things:
1) Will suspension be a consequence that is a meaningful deterrent to this child (with a child this young the answer is almost always no).
2) Will suspension motivate the parents to change their role in this. (e.g. if I have a child who is coming to school exhausted and acting out because parents can't be bothered to put him to bed, or a child who desperately needs services but whose parents have failed to show up to every meeting to make a plan to evaluate him, etc . . . then I'm more likely to suspend in hopes that the parents will be inconvenienced enough to change their own behavior.).
3) Is suspension necessary to ensure the immediate safety of this child and/or classmates, and buy us time to make a plan to ensure their future safety?
The last question is the one that I think applies. If I write a behavior plan that works, but that's dependent on a child exhibiting skills such as impulse control or listening to directions, or reading a schedule, and suddenly the child is in my classroom without the medication, or hearing aides or glasses that they need to be able to do those things, and as a result the behavior plan isn't working and children's safety is being jeopardized, then I either need to fix the lack of skill or I need to come up with a new plan. And sometimes I might need a child removed from the environment for a few hours while I do that. I can't require a parent to provide medication, or a hearing aide, or glasses for their child, but if behavior is "suspension worthy" I can ask them to take their child home long enough for me to write a new plan that doesn't assume skills the child doesn't currently have.
On the other hand, if I decide to suspend a child, in order to buy this time, and I call the parent and inform them of my decision and the parent says "Oh my goodness, I forgot his meds this morning! I'm so sorry!" I might say "if you're able to bring them to school and wait to make sure they take effect, then I can waive the suspension". After all, in that case the immediate safety concern would be taken care of, and the need to make a new plan would be eliminated. Although the tone of voice in which I'd say that would be entirely different, the message would be the same: "Bring his meds or he goes home."
I hope I'm making sense here. I realize this is a very fine line, and I'm not making excuses for what sounds like very unprofessional behavior on the part of the teacher, just adding another perspective.