My G4 iBook drive has also died; the original drive was replaced under warranty and the current drive has had minimal use... Go Figure. I doubt that I will spend the money to fix it and I am certainly not going to attempt the repair myself because you essentially have to dismantle the iBook.
There are online guides that provide illustrated step-by-step instructions; your partner should check one out before committing to the project...
Here is a guide for replacing the optical drive in a 12" G4 iBook.
The best idea that I have read is to print each page of the repair guide and use clear tape to stick the tiny screws to the appropriate page; you then remove the screws as you reassemble the iBook.( I think there are around 40 tiny screws of varying sizes that must be dealt with, so you certainly need a system in order to keep things straight.) ifixit provides a
"screw guide" to help you keep the screws organized.
I think that you can install different drives than the one that came with the iBook; I recall seeing a DVD burner option at Other World Computing. The drive costs around $100 and OWC will repair the iBook for an additional $50.
You can also connect an external optical drive to the iBook.