Brief Answer:
it depends

Detailed Answer:
Hello,

whether she should return depends on her general condition. If only the cough troubles her and your doctor has diagnosed a respiratory tract infection, then there is probably nothing worrisome. The cough may need some time to get better. If her general condition is better (no fever, no shortness of breath, etc) she should wait.

If - on the contrary - she feels more weak, she has fever or she has shortness of breath/pain during respiratory movements or other symptoms that raise concerns about a worsening infection she should visit the doctor right away. She should also visit the doctor if the diagnosis is not certain and other causes are suspected (like heart related cough).

Levaquin is a potent antibiotic and covers the most common pathogens of the respiratory tract particularly if the patient is antibiotic-naive.

I hope you find my comments helpful!
You can contact me again, if you'd like any clarification or further information or if you'd like to provide more details about her condition or progress.

Kind Regards!

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Brief Answer:
the cough make take a long time to wear off

Detailed Answer:
Pneumonia can be easily confirmed or excluded with a chest X-ray.
Post-infectious cough may last for up to two months, so this is not such a long time. If the cough is getting worse though as time goes by, then this could be concerning and it's another reason for her to do the X-ray.
Levaquin covers for most of post-infectious cough causes, so it's a good choice.

So in conclusion, if her general condition is good (no fever, no shortness of breath, no pleuritic pain, etc) then she can wait a little more. A chest X-ray would be a helpful addition to the investigation...

Kind Regards!

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Brief Answer:
so her clinical status should guide you

Detailed Answer:
It seems like you don't have many options but to wait. If any of the aforementioned ominous signs occurs though, you should take her to the ER.

Best wishes for a speedy recovery!

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