Answered by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him)
How can I stay awake after fajr until sunrise?
You can do this by reflecting upon the reward and benefits of doing so and by keeping this time alive with Allah’s remembrance with a group of people. If this is not possible you can drive sleep away by walking around in the place where you prayed. If you pray fajr with a small group of people you can delay the prayer so that there is not too long to wait until sunrise.