I just bumped my video's thread with a new cyberknife video. Cyberknife has been around for about a year. I wish I could find it but we had another here who was electing to go this way. Just like Tomotherapy and IGRT, this method is very precise utilizing CT to pinpoint the IMRT beam. Definitely cutting edge. I understood that two factors must exist for it to be successful 1: there has to be a defined location of the tumor, and 2: It must be confined. See the link below from Accuray:
Since your uncle is not confined I am not sure of the benefit. I am not certain that WPRT can be performed with Cyberknife, but standard IMRT may likely be combined with it. Perhaps the RO telling you about this can address how the lymph system is addressed using this technology. I could not find it online.