there could be infection in the ears.
First of all advice him NOT TO BLOW HIS NOSE.
AVOID WATER ENTERING INTO THE EARS LIKE BY SWIMMING OR TAKING BATH.
Then you can take antibiotics , ORAL DECONGESTANT tablets- like pseudoephedrine/ phenylephrine
, nasal decongestant drops like xylometazoline
Pain killer and anti inflammatory like voveron or ibuprofen
Get ENT consultation that would be better as proper examination can be done.
Take steam inhalations.
avoid air travel.