It sounds to me like he had neuroleptic malignant syndrome, which can be caused in PD and LBD by giving certain drugs. As I posted in other threads, a neurologist at a seminar I attended last Friday was very explicit that anyone with Parkinson's [or LBD] should not be given Haldol, Risperdal, Zyprexa or Abilify. My husband was given Risperdal in 2008, developed NMS and nearly died. Like your husband, he became very rigid, unable to talk or swallow, and ran a fever. Scary!!! I'm the only one that found the cause by researching his meds on the internet. I ran across a British medical journal [I think it was Lancet
] article about it. As soon as the drug was stopped, he improved but some never do recover!
Sadly, there are still quite a few practitioners who haven't gotten the message.