I can't give medical or psychological advice. However, here are some suggestions that may be helpful:

1. Establish a good schedule: let children go to bed and get up regularly every day to ensure adequate sleep time.

2. Limit study time: Children need proper rest and relaxation to avoid long-term continuous study.

3. Encourage children to participate in sports and other recreational activities: These activities can help children release stress and anxiety and enhance their physique and immunity.

4. Seek professional help: If the child's study staying up late has affected his health and learning effect, parents are advised to consult a doctor or psychologist.