Your mother is suffering from COPD and the symptoms of your mother is suggestive of acute exacerbation of COPD.
In COPD patients acute exacerbation is diagnosed by increase in amount of sputum and change in colour; increase in breathlessness and cough. Fever may be associated. In COPD patients exacerbation is usually caused due to lung infection
. Consult a pulmonologist
immediately otherwise the condition may get worse. In my patients with COPD I always make them vaccinated with Influenza
vaccine yearly and with pneumococcal vaccine
every 5 year.