I'm just in awe that you had the balls to meet the guy face-to-face!
If an individual is commited to a psychitaric institution by the court, then any records related to his diagnosis and treatment fall under the HIPPA confidentiality rules. But the legal proceedings should be a matter of public record. The only reason I can think of that the legal record would be sealed is if the offender was a minor. Doesn't sound like thats the case.
As other have suggested, you might try consulting a lawyer if you have the means.
"Carry on my wayward son
There'll be peace when you are done
Lay your weary head to rest
Don't you cry no more"Kansas