[chgomom]

Ok, really. If what he is saying is true, and his blood pressure is the way he describes then he is having episodic orthostatic blood pressure and it needs to be evaluated.
Any number of things can cause it. Kidney impairement, adrenal inusfficiency, dehydration, potassium imbalances, diabetes and a myriad of of nervous system and cardiac issues. Even if it's something as simple as dehydration, if it is indeed fluctuating the way he describes, with his GI and blood suagr concerns. He needs to not self medicate, run it by a doc so they can run basic chem panels, check his electrolytes before he waits self medicating with his diet.