Antibiotics do only work for bacteria. And since they kill of the beneficial bacteria that control fungi, the antibiotics can make fungal infections worse.
I am not a fan of putting liquids containing water in the ear though since any water remaining in the ear can breed bacteria and fungus.
A few options would be to add a pau d' arco tincture to a small amount of olive oil to drive off the water and alcohol then use the warm oil as ear drops to kill the fungus and to soften up any ear wax. After about 20 minutes I would use a bulb syringe to gently suck out the oil.
Or make an extract with pure alcohol, no water, to use as ear drops.