I know I'm coming late to the party, but where did OP state that the reason the other boy has a 1 on 1 is because he has been deemed to be a danger to the other children? You obviously don't spend much time with children who need a 1 on 1. Generally, being a danger to the other children is waaay down on the list of those reasons.
A well-written IEP will take into consideration the need to try different strategies over the course of the year to achieve the desired goals of the IEP. These strategies would be included in the original IEP, rendering additional meetings in order to change the IEP mid-year unnecessary. If your child's school isn't doing this already, the document and your meeting is nothing more than wasted paper and time.
Do you have proof it wasn't? No one knows who that other adult was.
Again, since you don't know who the other person was, or what they were discussing, this is a judgment you just can't make.
Again, you just don't know how the child's IEP was written, who that other person was, or what they were discussing to make that judgment. Just because you feel she should have been standing a foot away from the child doesn't mean she was not doing her job.

This is by far the best advice I've read on this thread. It supports the child's version of the events without the parent becoming THAT parent at the school.
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I'll be honest, at this point, whether or not the para lied would be the least of my worries with OP's son. My concern is more that there seem to be issues regarding school that is causing the child stress. The meeting with the principal should be about that and how that stress can be reduced.