My little brother has a fever how can we break it? been giving him motrin and tylenol (acetaminophen)

Fever.: Cure the underlying illness. Fever is just a symptom. It does not necessarily need to be treated. If he is miserable with his fever you can use an anti inflammatory med or Acetaminophen or a combination of both ( as you are doing) with the goal of making him feel better. If fever is due to a virus there is generally nothing but tincture of time to break the fever.