I know that I have had to train people on the concept of twice exceptional. It is misunderstood. I went in with so much info that I had> I also had to give info on misdiagnosis and the underachieving child. They seemed to educate themselves when they knew I was on top of things. Yes if the IEP says an aide goes with him to whereever then that should be happening regardless. this is from a sped teacher. If he is not succeeding in the pull out and there is no aide there for support then he should not be removed until given all accomadations and modifications as stated in his IEP.
As a little hint that you are unhappy ask for a recent copy of the IDEA book so that you can review your rights to due process. That will let them know there are issues with the IEP. Then follow through with the parental complaint if necessary. I am a sped teacher but know that sometimes people need a fire lit under their butts to make a change.