My aunt's annual health check showed RBBB on ECG. Doctor said nothing to worry because she has no symptoms of any heart disease. I am not sure why your son wouwas put on medicine. Was he having some symptom..? I guess so, otherwise you would not have ECG for a young child. Right? But from whatever we learnt about RBBB from doctor it is probably not very serious defect and my impression was that most people with it will have a normal life.
what is RBBB please expand, I could search from the google that it is Right Bundle Branch Block, Is it the same thing.
rbbb is found normally in a large number of population, and there is nothing to be done, they lead a normal life, it is just an incidental finding on ECG