Since when is he having the night sweats and chills?
Do they occur during the day too? is he perfectly healthy during the day?
Does he have sore throat or cough or sinusitis? Any body ache?
Has he felt better after taking the Nyquil?
This sounds like he is setting up for a viral infection like flu. Sometimes viral infections can occur even without a sore throat or other symptoms of a respiratory tract infection.
Normally a viral infection should subside by itself in about 7 days. Please continue to give him the Nyquil - you can give him a Nyquil every 6 hours, meaning 4 times a day. If the Nyquil cannot keep the chills and fever within control for the next 2 days, please consult a doctor.
I hope this helps.
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