Simple, their sick
Productive means, devoliping or always. Like always running thats being productive, so if their cough is productive it could mean it's very common for them to cough a lot. Like drawing, you draw, you do something, not once or twice, but like 85 times a day. (Over exaggeration)
So it may be the same with the coughing.
If possible brainliest please?
