Hi welcome to Health care magic forum.
Thanks for calling H.C.M.Forum.
Your father aged 66 yrs, had laberinthitis 10 days ago, With bed rest
he has improved but he lost appetite.
Laberinthitis is an inflammation of the internal ear, causing dizzyness
sensation, which may be felt as loss of appetite.
I advise you to consult an E.N.T.surgeon for diagnosis and treatment.You may need to have an M.R.I. besides other routine tests for confirmation.
There are medicines for dizzyness, like cinnerzine, and betahistine
to over come the dizzy ness and vomiting sensation, and hence loss of appetite temporarily, till the infection of labyrinth is cured.
Wishing for a quick and complete recovery.