With all due respect K, I believe you need to focus more on you than on how difficult child affects you.
You said he called just now, is he not in school today? I agree you need to prepare and educate yourself for the next meeting. Your difficult child sounds alike like my difficult child back in second grade. He would get upset at something small, shut down or rage, leave the classroom, miss instructional time, then upon returning would be frustrated because he missed lessons.
It's so important to get a handle on these kids and keep them in school. Go ahead and do your best to prepare for this IEP meeting. But you also have to focus on yourself. You are going to have to detach from interacting with your husband and detach from resonding to difficult child other than setting down the rules. When he responds negatively, shut down and walk away. Let him yell to the empty space all he wants. You lay down the expectations and the consequences and beyond that, nothing.
This may help you in the short run. In the long run you will have to find the time to take care of yourself. You could be dealing with serious anxiety and stress from dealing with your son and your husband all this time. Get a handle on that, please make an appointment with your doctor.
Sharon