Yes, these things can trigger a panic attack.
However, no, this doesn't really sound like that's what happened. Did they check for stroke or TIA? Has he seen a doctor outside of the emergency room? OFten, they aren't able to diagnose in the emergency room because they have more important things to do- after going to the ER, you should really follow up with a specialist.
I'm not ruling out panic, however, it sounds like something else could be going on.