Yes, it has been stated many natural or developed Lucid dreamers meditate and use their lucidity to develop themselves and become a better or broader person.
As said before she could take a passive role and watch her mind work and relax watching. She is as you say in full control.
Lastly, I have always felt energised after lucidity and so happy. It is strange she feels drained.
We dont dream all night so she should have the same time as us in non-REM sleep to rest.