I would be loathe to mention anything but a mood stabilizer given what you’ve told us - he shot pretty high up w/psychosis and then refused meds to come down or get stable.

Besides, the psychiatrist needs to be willing to prescribe it as well.

He may need to be readmitted as it stands - that depression after extreme mania is pretty horrible and should be seen/assessed by a psychiatrist to be sure he is safe. Especially since he isn’t taking the Lamactil