I am sorry to hear about your brother. Encephalitis is an inflammation of the brain. Children with JE can develop seizures. The inflammation and the seizures can lead to destruction of brain cells, called neurons. Unfortunately we do not know yet how to fix or get neurons to regenerate, but there is some evidence that in children the brain has the capacity to restore some of these destructed neurons. In the case if JE, the long term outcomes are divers. Although some symptoms improve after the acute illness, 30%-50% of survivors continue to have neurologic, cognitive, or psychiatric symptoms (according to the CDC). There is some suggestion that training the brain by doing puzzles or memory games the regeneration of the neurons increases. I can’t give you hard evidence. For your brother the most important thing is that you love and respect him for who he is and you might be able to help him out with the subjects that he finds hard to do. Make it fun for him and get some quality time out of it!