This is not psychological. This is what medics say when they don't know what it is and haven't consulted the relevant specialist. She has neurological symptoms, she needs a neurologist. People are far too trusting that doctors a) know enough and b) know when they don't know enough.
Quadriparesis/quadriparalysis, syncope and sleep myoclonus is not going to be a manifestation of a psychological disorder. It's a central nervous system issue.
It could be many things, they need to test her reflexes and muscle tone and do an ECG. Wait for the blood tests to come back and if it's not an electrolyte imbalance do nerve conduction studies or EMG, lumbar puncture, a spinal MRI not CT.
It could be post surgical hypokalemia (low potassium). Hypokalemia is common in anyone after surgery. Her potassium would have to be VERY low to cause symptoms this severe, but it fits everything. Nausea, syncope, quadriparalysis, parasthesia, myoclonus. If they did an electrolyte panel, which they should have done, this should be obvious. And simple to treat.
Another strong maybe is transverse myelitis. Would expect some bladder and bowel involvement, though. If the electrolytes come back normal then starting precautionary steroids while waiting for diagnosis would be a reasonable decision.
It could be rapid onset GBS. In which case, they should also check her thyroid function because this can be a trigger alongside coinciding factors. In fact, her presentation is quite text book for this with nausea and syncope and quadriparesis/paralysis upon rousing. Not so much the myoclonus though.
Could even be radiculitis/CNS infection if there was infection in the ear and it reached the CNS due to surgical disruption. Especially if her surgery was for chronic otitis media or involved the mastoid bone.
Whatever it is, it is not psychological. Hope she gets an answer soon.