thanks for writing to H.C.M.
I have gone through your query regarding persistant cough
of your 62 years old mother. I would like to tell you that cough is produce by the pathology of-
You have to do a tharough cardiorespiratary examination to find out the real fact. Your mother is 62 years old so she may be having some cardiac ivolvement that has to be ruled out.
I would like to suggest you to consult doctor
of internal medicine for this purpose.