I would still record the fact you asked about the symptoms listed.
At my former employers (DWP) we had a standard checklist to go through when someone first reported being unfit for work.
We then had a Welcome Back Discussion when they returnt to work and again, that had a standard format to ensure certain areas had been discussed.
I would say it's better to ask one or two more questions for confirmation of his condition.
You can then reassure anyone who is concerned about the risks that you have acted reasonably in the circumstances.