Mild fever with Tiredness. Going out.

My father has been feeling sick with mild fever ranging from 99 to 100 degrees Fahrenheit from last two to three days.His age is 60years.Aside from fever, he also have little tiredness. Aa soon as he noticed mild fever on first day itself, he has taken paracetamol and then Temperature dropped under control but again next day afternoon he got mild fever(100 degrees Fahrenheit). He again taken the same medicine to control fever. Temperature is getting under control as soon as he takes medicine.So, with this mild fever on and off situation, we are little worried if this is a general flu like cold or not. No other symptoms other than mild fever, little tiredness and sometimes he is not feeling hungry by the time he usually takes his lunch daily. No travel history internationally and even no travel history within India from last six months.Once in a while he goes out to get domestic needs but he is making sure to wear mask when going out.