CRP (C-reactive protein) is a protein found in blood whose circulating concentrations rise in response to inflammation. CRP levels usually peaks within 48 hours. It quickly falls once inflammation subsides.
Looking at your father's symptoms (Fever, Dry cough and raised CRP), first differential diagnosis will be COVID-19 infection if you are residing in a location reporting community transmission of COVID 19 during the 14 days prior to symptom onset.
Next Steps
Visit a nearest physician or community clinic or fever clinic and get him evaluated in respect to these symptoms at earliest.
Doctor might ask you to get COVID-19 antigen test or COVID-19 RT PCR test along with a Chest X ray or CT scan.
Health Tips
Ask your father to isolate himself in a room. Only one home caregiver should provide necessary care. When in or near the patient's room, wear face mask and gloves. Download Arogyasetu app on your father's phone and inform about his symptoms. They will provide you with details of nearest COVID screening and testing center. Also your nearest physician can provide you these details.