How to Update firmware of microcontroller using DALI lines of a DALI slave module?
This requirement is addressed in the upcoming IEC 62386-105 standard which specifies a method of transferring firmware over DALI. However, it is some months away from being released, and would still require you to implement firmware which can write the PIC program space, and probably also to write the PC software although the main lighting companies may eventually release their own which could be used.

The standard leaves it open as to whether you partition your program space into a bootloader (which would have to have DALI capability) and one application, or two application spaces with one active at any one time, each acting as bootloader for the other. 

Unfortunately this has been one of the later standards to be written in the 62386 family so companies may have implemented proprietary methods in the meantime. So unless you have the required information which is likely only available under NDA, you can't use those PC software programs with your device.