I'm glad you are seeing a GP. My husband was diagnosed as having panic attacks, was even treated for them. He still kept having them. My aunt witnessed one during dinner and said, I think he's having a seizure. Sure enough, he went to a neurologist and, after testing, found out he was having seizures. Once he was treated for seizures, they stopped happening. He did, eventually, grow back out of those. It definitely didn't look like any seizure I had ever seen. Anyhow, he no longer needs meds.
As far as how your husband is acting, maybe he doesn't want to believe anything is happening or doesn't want to further upset you. Not knowing your husband, I wouldn't be able to tell. I do know my mom was like that, quite often, with me and she was a nurse. I think she was more into denial.
I hope that everything turns out for you and they are able to find answers.