Do not worry. This is a common problem. He need to reduce his exposure to mobiles and laptops. Take adequate sleep.
Next Steps
Take frequent break while working on laptop and mobile say 1 min after every 20-30 minutes. Need to check for convergence deficiency and start the exercises for the same.
Health Tips
Start using lubricating eyedrops like Systane Ultra or Refresh Tears 4-5 times per day