Hi Teja,
I have read that exposure to temperatures over 100f for a few hours can cause these symptoms. By that I mean nowhere he could get away from those temperatures.
I did not mean that he caught anything from the spiders it is just that the spider morph is associated with a neurological condition known as "spinning".
This has also been seen in other animals so I wondered if it could simply be that - but the vet is the one who has examined the animal and there are plenty of examples listed of it being a bacterial or viral problem as well.
Can you think of anything you were doing / changing just before this started?
I hope he pulls through for you.
dr del