I don't know. Let's put ourselves in his shoes. Think of a good friend of yours and their Husband. Now picture her completely changing out of her character with no real reason. She gradually gets worse over months and eventually ends up in a coma. Would your mind not go there?
Now picture having that suspicion but not sure of how to address it. If you go to the police right off the bat, you're going to make an enemy with the Husband and possibly look crazy. So you do research online to see what kind of poisoning could fit the symptoms. You find something that may fit, the next step (not us because we're morbidlike, but a regular Joe) is to start a think tank with people who might know. What better place to ask, but MDS? I mean, Websleuths are too nutty to keep in check. They'd find out who you are and start calling authorities in between missing a loop in their crochet project. Not like us, who keep their cool and not lose their shit.
Maybe we're the "courage by proxy" this guy needs to tip off the authorities. Depending on what we think of the situation. I'm not writing him off. We don't know any background though. Did they have problems in the marriage? Does he have a big life insurance policy on him? Etc. That would be helpful to know. There has to be a motive if he was being poisoned.
I would think someone wouldn't go through the trouble of asking unless there was a reason for them to believe someone wanted him dead.