Looks like an ear infection to me. I've treated birds with this. Hold warm wet compresses to his ears to get the gunk to soften up enough to remove. You may have to use a toothpick to gently pick it out of his ears. It will be a hardened plug. Once his ears are open, rinse them with either some warm betadine water or some hydrogen perioxide. Finally, pack the ears with Neosporin. He should be o.k. after that. I never give antibiotics, I find they are great healers on their own.
While you are working on him, open his mouth and check the roof of the mouth. There's a deep slit in the roof of the mouth. If/when they get respiratory infections, that slit also fills up with gunk from the drainage of the nose/eyes/ears. Once it stops up, the nose/eyes/ears back up. If it needs to be cleaned out, a toothpick works great there also. Then apply Neosporin there as well.
Best of luck.
While you are working on him, open his mouth and check the roof of the mouth. There's a deep slit in the roof of the mouth. If/when they get respiratory infections, that slit also fills up with gunk from the drainage of the nose/eyes/ears. Once it stops up, the nose/eyes/ears back up. If it needs to be cleaned out, a toothpick works great there also. Then apply Neosporin there as well.
Best of luck.