You need to give him decongestant also, plain deselex ie loratidine
will not help much , you need to give him decongestant in combination too like phenylephrine
7 day- 10 day course of antibiotic is good enough not much
Secondly do take care of reflux disease in children , you may feel that such small child will have acidity and reflux but the answer is yes and reflux is one of the big reason for long term throat problems and ear aches.
Later you can also get done x ray
for adenoids soft tissue nasopharynx
lateral view. as----
adenoids are present behind the nose ,upto age of 7 yrs.
if enlarged they block the drainage
of mucus from nose and so he develops nasal infections and is not able to breath. he must be a mouth breather and a snorer. There is a tube connecting the middle part of ear and behind the nose where the adenoids are present and if the adenoid are enlarged they block this tube so negative pressure generates behind the ear drum and fluid accumulation in ear and causes ear infection
So consult an ENT specialist
and get the x ray done.