If the medicine is more than 6 months old or out of date, it should not be used at all. Each ear infection should be evaluated when they present because ear issues can be bacterial or fungal. If you put the wrong medication in the ear, you can do more harm than good.
Don't use the vinegar in the ear any more. Go ahead and see your vet for an exam. Take your meds with you so that the vet can tell you if they are the proper ones to treat what's going on. If so, great! If not, you can get appropriate meds.
If he has common ear issues, you will want to talk to the vet about there being an underlying allery cause.
Let me know if you still have questions.
