I really didn’t know what forum topic to put this under, but since children with disabilities may become parents with disabilities, who in turn then have their own children, who may have disabilities and IEPs, I put my question here. 
 

Is the IEP and 504 process completely focused around the student? What if the parent needs some sort of accommodation in the development or execution of the child’s plan?  Maybe it’s written only communication because of a hearing issue or more frequent progress communication due to anxiety?

The parent's disability is covered under ADA.  If they need written communication or a translator of some sort (ASL for deafness) the school needs to provide reasonable accommodations.  Obviously, they would need to say this before the meeting.  A parent with memory issues or who has difficulty taking notes could record a meeting as an accommodation, for example.

In my experience, ADA works closely. My most recent experience was in our virtual school. Dad was learning coach but had some learning and cognitive disabilities, so the teachers worked particularly close with him and his caseworker.

Parents could also get assistance by putting “parent training” scenarios in the IEP. 

Parent training is a component of IEPs. You have to make the case that it's required in order for the child to access FAPE.