Hi! I'm a pediatric nurse and this is what I've learned about the use of those meds. The decongestant is used if there is fluid behind the ear drum. It helps get rid of it so he won't develop an infection (if he hasn't already) and the drops, if they are for crankiness, are probably Auralgan drops which are pain drops. Fluid in the ears can cause pain like an infection but the decongestant should help in about 24 hours but it won't help if he has an infection also. If he's not any better I would take him to his doctor and have them check his ears. If it's just fluid he shouldn't need an antibiotic but if it's infected then he would. Also, just because it wasn't infected at the ER doesn't mean it's not now, ears can change from one day to the next. So if you don't see improvement, go to your doctor.
Good luck!
M.