Is CIDP the chronic version of GBS? *also posted in GBS child

I posted in GBS child because my son resembles GBS. (please see that post for more details) I am thinking of calling my geneticists to run the name across his desk and see what he thinks.
My son died in February at 7 months of age without a diagnosis. We were told that no one has ever seen a case like Logan’s. What was so puzzling was his chronic SIADH w/ hypertension, hyperthermia and extreme low muscle tone. He had low gut motility and urinary retention all his diagnosis have no known etiology.
We’ve nearly had every test done under the sun trying to figure this out.
I’m curious how patients under 1 year of age are able to be diagnosed? (The neurologist refused to do an EMG on Logan)
We spent 6 months in the NICU at Arkansas children’s hospital…(we were denied transfers to bigger hospitals… we tried to transfer twice) We were given little to no hope so we took him home and made due. He had three weeks at home before his respirations diminished and he went into a code.
We had an autopsy done but we do not have the results. I’m not sure what is being looked at and tested? He had an MRI of his spine, but it was not a good MRI because Logan would stop breathing when sedated (I would not allow any sedation without intubation). we were looking for tethered cord, when they had enough information to say he did not have that the MRI stopped. He also had a spinal-tap at around one month of age looking for meningitis. Not sure if that fluid was sent to the lab or not? I’m very interested and if anything learning a lot about what people go though. Please see his blog @ logansworld.blog.com