My boyfriend has been practically a zombie for the past 9 months and doctors couldn't help him

Hello, 4 months or so ago I made a post about my (17F) boyfriend's (19M) health quickly degrading after a traumatic event. We've been going to general practitioners, psychiatrists, therapists, hospitals and no one could help him.

4 months ago my boyfriend would present the following symptoms : - was unable to talk besides a few short words, mostly communicated via sounds - migraines and abnormal (longer) sleep - felt urges to harm himself. He would be completely harmless to others but dangerous to him - frequently broke down and shout, then got back to silence

We've been seeking help from general practitioners first, who advised us to go to psychiatrists or do a MRI. We've seen 2 psychiatrists who couldn't tell what was going on, one of them even implied we could be "faking the disability to get financial compensation", which broke my heart into pieces.3 weeks ago we finally had an appointment for a MRI, which turned out perfectly normal, his brain appeared completely healthy. We tried therapists too, but they couldn't help us since my boyfriend wouldn't speak.

However since my last post in September his health got downhill : - he's completely mute, can only communicate sometimes via small sounds - he regularly "disconnects" for 5-30 minutes, just stares at somewhere and doesn't react to any exterior stimulus - he's been having difficulties to move, like he has marshmallow legs. (I bought a wheelchair) - his sleep is still abnormal, but now it's shorter, and he's been having night terrors - doesn't eat or drink by himself, I have to feed him - plus all the previous symptoms are still there

I feel completely hopeless. I've been seeing a therapist and a psychiatrist and taking antidepressants but I don't feel like it's helping, I feel he'd need the meds more than me. He's been living in my room for the past 4 months and my whole life is watching over him (I'm homeschooled). I still love him because I remember the amazing man he used to be, but watching him becoming a zombie terrifies me. Sometimes he's staring at me with confusion and I wonder if he even recognize me. Does anyone know what that could be ? It happened after a traumatic event but I've never heard of a kind of ptsd going that far. I'm ready to do anything for him.