Any chance of Cerebral Palsy being missed or misdiagnosed in childhood?

Hello everybody, first post here, thanks for letting me in   I'm concerned about my son and wanted to ask those of you with first hand experience what you think.

My lovely lad is 22 and is diagnosed with autism, learning disability, 2 different kinds of epilepsy (one confirmed, one suspected), sensory processing disorder, auditory processing disorder and language disorders (I forget exactly which terms were used now but he has severe receptive language difficulties and his expressive skills are greater than his receptive ones).  The biggest problem he has is fatigue and fluctuating mobility issues.  He used a mobility buggy until the age of 8, and then from around age 11 to about age 15 he was incredibly unwell, very fatigued, collapsed a number of times, had days when he could barely get out of bed and so on.  He had these odd fugue states that would go on for hours where it was as if he'd been tranquilised.   I had to use a wheelchair during that time as he'd tire so quickly and would sometimes just go over without warning.  Numerous tests and assessments came up with no reason for this; eventually a neurologist suggested non convulsive status epilepticus and started him on epilepsy meds, which did help with the fugue states but recovery for everything else took years.  He still tires quickly and when we're out walking he will often rest his left hand on my right arm for support.  We have to be very careful about the amount of activity he does because he gets so tired his whole system starts to shut down and things he can usually do for himself, like getting dressed or making himself a sandwich, become really difficult tasks.  You can imagine how frustrating it can be for him!

I took him to a private physio during that ill spell and she found he was weaker on one side than the other, which tallied up with pain he seemed to be experiencing down one side as well.  He does seem to lean slightly when he walks although it isn't always obvious.  I've also been told he has low muscle tone and when he was younger he was incredibly flexible; I'm not sure if this is still the case as if I ask him to touch his toes or something like that he usually tells me to get lost   

I keep finding myself wondering if he might have a very mild case of Cerebral Palsy and if it's possible it's been missed in amongst all the other diagnoses?  I've been going through his notes from birth onwards and looking up things that have been noted re development and various problems.  Lots of things come up online as being possible indicators of CP but then of course they're also possible indicators of other things he has already been diagnosed with.

I would really appreciate any advice you can offer.  Is there any chance this could have been missed and, if so, is it possible to get an assessment for an adult?  A part of me is loath to have to start pushing for assessments again as everything is such a battle.  At the same time, I'm so tired of having to explain how tired he gets to other people. I seem to be viewed as an overprotective mum who won't let her precious son spread his wings, but then none of them see him so tired he can barely function.

Thank you for reading.  Sorry for such a long initial post but I've been trying to work out what to do for a while now and decided that those with the condition are always the best experts, hence coming along here to see what others think.  Thank you in advance