An allergic reaction to.. I'll get to that in a sec. It was three years ago in the summer, we were having a major heatwave. A few weeks before he died he remarked that everytime he drank water his throat and tongue would swell up. He said he's paranoid someone could be poisoning him. He told me milkshakes don't cause the swelling so he bought a ton of milkshakes. One night it was super hot and he woke up dehydrated, telling me he's out of milkshakes so he's going to have to have a glass of water and then go back to bed. That was the last I ever heard of him, he was found dead in bed from asphyxia. It wasn't until much later I learned there's an allergy to water called aquagenic urticaria, and once I learned of that, it makes sense.