My husband and I were arguing then he stopped talking and kept mouthing words then collapsed and his pupils dilated and his hands cramped up, was this a panic attack?

STROKE OR TIA. Maybe panic attack but sounds like it may have been a stoke or mini-stroke or tia (transient ischemic accident). Did he recover immediately afterwords or what happened. Need some more follow up information but I would definitely speak with you doctor.
Tell me more. How is he now? It could at least be some type of reaction to the stress of the argument. If he recovered quickly without any further problem then maybe it was. But either way, you should cut the poor guy some slack. Well that's my opinion anyway.