He has an infection from the odor you describe and your Veterinarian will tell you if the eardrum is intact or not.
What has to be done if the ear drum burst? In a dog.
Eardrum ruptures are not common with simple infections. However if an eardrum has broken or ruptured, they heal slowly on their own. there is no surgical correction. a simple exam by your vet will determine the situation very quickly.