Letters from the MH team prove nothing. Most of mind just say something like
Saw x in clinic today.x attended with her partner/on her own. X reports feeling ok but has had occasional sleep problems. X says she is doing well on her medication and has attended routine blood tests.
That’s about it for 99% of them. They tend not to write the juicy stuff in detail anyway.
What is this feature associated with a mental illness? Could it be your DH telling you she’s making it up because she’s delusional at all?
Ok here’s what I think. Your DH works in MH. Somebody, a patient has contacted you saying he’s been shagging her. He’s telling you she’s nuts.
If that is the case then I strongly suggest you, or he, reports it to his boss. Either there’s a psychiatric patient making up stories about the staff, which could cause someone real trouble, or your DH has been shagging patients, which is not only as unprofessional as it gets, but it’s morally deplorable. That’s not even addressing the fact that he had identifiable medical information in his car.
Of course I could be miles off the money, but that’s what I’d put mine on. If I am right then it needs dealing with in the proper way. Psychiatric patients are incredibly vulnerable, and they’re so easy to discredit that they’re hardly ever believed. Personally I couldn’t sleep at night if I thought I was complicit in their abuse, not even if it was just a tiny doubt.