My Brother Recently Had Some Episodes Of Dizzy Spells, Which

My brother recently had some episodes of dizzy spells, which were more of an off kilter type rather than a room spinning. this has happened a few times. Recently he had clamminess in the neck area and went to the ER. They did do an EKG and determined he was not having a heart attack. Being somewhat knowledgable about the heart, I understand there could be heart issues, and it would not necessarily show up on an EKG. They did suggest dehydration which I believe from what I know working in the medical field is a real possibility. He takes HCTZ, which I know can cause dehydration. Anyway his syptoms have been feeling off kilter, dizzy so to speak and then when he was in his garage and working felt clammy in his neck area.

thanks for your time, Karen