Though I know you have significant experience with special needs, I'm going to bet dollars to donuts that the combativeness was caused by the caregivers and the transport crew more so than the patient.
There are a lot of specifics not in the scenario, so I'm going to make assumptions just for the sake of argument. (Not criticizing, but explaining why I would make nonsense assumptions).
My first comment is that I wouldn't have moved this patient from a familiar environment until he was fully alert and calm. It sounds to me like he woke up in restraints in a strange place...You can bet that I'm going to kick your ass too and get back to where I feel safe. This takes time, and that might piss some folks off, but screw 'em. That's how to care for such a patient, and that's our job.
Also, don't you have a medication protocol for combative patients? IM/IN? If not, that should be discussed. For obvious reasons I'd talked to my medical director years ago about creating an autistic protocol. He said, "You have a protocol for combative patients, right? If you can reasonably predict violent behavior, use it. Why would you choose to wait until someone gets punched in the mouth to mitigate the violence?" Also with medications, the mental and emotional damage that can be done to these patients, in Dylan's case it would last at least years if not be perminent, is massive. Allowing that damage to happen is not patient advocacy, right?
I've also never been around a patient that was able to reason, even at a minimal level, that was unable to communicate. Normal means weren't missing in this patient, only verbal means. We communicate in other ways all the time. Facial expressions, eye movement, non language sounds....it sounds like he was communicating just fine. "I'm terrified and need to get out of here!" It's just that no one was listening and treating him accordingly. You should be able to communicate non verbally to him as well.
I recently treated my first mentally handicapped patient in PNG. Just on accident. I'm not sure what flavor his pathology was....Very spastic movements, fisted hands flying in violent, apparently aggressive ways, angry, non language sounds. He actually came under my care just on accident. He had one eye swollen shut from someone punching him in the face from this behavior. When I stopped at a local market he came walking quickly towards me. It appeared from his sounds and body movements that he wanted to attack me, but when I looked in his face it was pure agony. He seemed to understand that his behavior was chasing off everyone that he was seeking help from, was trying with all of his might to control it, but was unable to do so.
I didn't really know what to do, and when he got near me, a villager thinking that he was going to attack me punched him again and knocked him down, and that got other people riled up...his face seemed to say that he needed help so when he got up I lunged inside of his flailing fists and just hung onto him. Once his body had something to hang onto he clung on for dear life, buried his head in my neck/shoulder, and just sobbed/screamed for a while.
We stayed that way for, maybe, 5 minutes...(Not sure really, but it seemed like a while.) After he calmed down I sat him down and someone from his village ran up and was able to translate for him that he had bad severe head pain from previous beatings. I set him up with Panadol (Tylenol), Ice packs, and some codeine for night time use, hydration instructions, etc, all given to his care provider who I had at least minimal confidence could follow instructions. (Taking him somewhere for further acute care, or other long term care is not possible for this patient in this environment) Fortunately for him, having made friends with the "white doctor" (Yeah, I know, their language, not mine) gave him an improved status and will hopefully improve his life, along with the example of his being damaged, and not mean.
Anyway, the point being that it's difficult to get further away from traditional language than being with a mentally/neurologically damaged person that doesn't even share a culture, but it's absolutely possible...it just takes time, and an honest desire to help as opposed to completing a run. Know what I mean?
Excellent question.