On and off feeling of body swaying.

Hi Am writhing on behalf of a friend... So my friend had an ear problem of hearing dual sounds and muffled voices for which he consulted an ENT and as part the doctor took an injection though that helped for sometime but dint last long he then went for second opinion after which the muffled voices vanished but started hearing a ringing sound and eventually with medicines this also vanished however he started feeling like he would fall off n his body is swaying and kind of dislocation of his brain. He also got a HRCT temporal bone scan but this reports are normal. So my question since we thought this might be because of an ent issue and is vertigo after the reports we are not sure, can somebody suggest what specialized doctor should be consult or what is the solution for it as he is going through this since last November. Thank you