Hi, I'd like to help you with your question.
At his age, your grandson has limited understanding of how illnesses such a stroke affect someone. So in order to explain this to him, it needs to be done using simple terms.
I hope this has helped you,
When we say the teacher is sick, then when he is sick or Grandpa is sick, I guess that is why it's important to give the sickness an identity? For instance, a stroke is a serious kind of "sick" whereas a cold is something everybody gets?
Yes, it is important to let him know what kind of illness so you can separate an illness such as a cold from something more serious. Just be sure you don't give more comparisons than that because it could confuse him, unless he asks for more. Let him know that a cold is something every one gets and it goes away in a few days but a stroke involves the brain and takes longer to feel better- a simple explanation like that. He should do fine understanding that comparison. He may want to know more about how a stroke works and that is ok too. Sometimes kids feel anxious that they might get the illness so it's important to let him know that adults get strokes and they happen only for certain reasons, etc.