Welcome in H.C.M.
I have gone through your query regarding recurrent respiratory tract
infection along with fluid in ear of your baby.
As you said in complaints it appears still your baby is having infection in respiratory tract including lungs and infection has reached to ear via eustachian tube (Tubular connection between throat and ear).
To confirm the disease process and planning for treatment you should do-
1- Culture & Sensitivity of throat swab.
2- Sputum for Afb.
3- C.T.scan chest. & paranasal sinuses
4- Impedance audiometry
5- Blood- CBC, ESR
, blood sugar (f & PP).
After the inferences of investigations final treatment may be planned but you are advice for steam inhalation and use of mucolytic