Hello, and thanks for your medical question on eHealthForum.
The history provided seems that your father is having a infection due to Mycoplasma , a form of bacteria, that can cause pneumonia in elderly patients (above 60 years), who have a reduced immune function.
Proper supportive care (Nebulisation, Mucolytic medications, Anticough medications) and adequate antibiotic coverage would be necessary to treat such an infection.
You might consult a physician for proper evaluation and treatment of your father's condition.
I hope this helps.