what would cause superficial dilation to the point of needing a wet suit to swim in even very warm water, and be unable to lie down with head lower than hips?

-- I would think blood vessel constriction would be more of a problem in those scenarios; it would be the inability of blood vessels to carry blood actively that would cause a problem with heat and fluid distribution . . .and, of course, clotting, arterial sclerosis, and vascular disease from autoimmunity or impaired glucose regulation might all be culprits there . . .

Can you be more specific as to what's happening?

he feels cold, even though his skin surface feels very warm....

This can happen centrally in some brain damaged people.(strokes and head injuries etc)

no obvious stroke, but they can be discrete. Head trauma: car accidents and war zone....possible. though we joke about mine (head trauma) i would think it would have come up.....though the w/z part is never discusssed.....
dont think that is it though, i think this is more recent. thanks, and arent you supposed to be on vaca, and enjoying yourself? lol

Yes, still on vacation....but we stop by the laundromat in town now and then and I can log on with the free wifi here.

Flushing all over, with heat sensations that can be felt by others can be also a sign of serotonin syndrome... or overload of serotonin from a tumor someplace.

High dose nitrates may do it too.

Drug reactions from sulfa do this and other drugs may be culprits in allergic patients.

RSD patients have temperature changing sensations too. Red skin that feels cold to the patient, etc.

We are having a good time... considering the strange weather, which is either very hot or very cold (like today!)

My feet are not happy however, with all the rocks here I have to walk on.