Context: A music video for the song was released on the same day. The video features the band performing the song in a nursing home (abandoned St Luke's Hospital in Pasadena, CA), in make-up making them appear as elderly versions of themselves, and end up inciting a riot amongst other patients and orderlies. Multiple outlets, including Billboard and People magazines, felt the music video was an homage to One Flew Over the Cuckoo's Nest, while Team Rock noted its additional similarity to the film Cocoon. The video ends with a brief choreographed dance routine, noted by Variety and ABC News as being similar to the routine done in Michael Jackson's video for the song "Thriller". The video was directed by band frontman Dave Grohl. The old age makeups were designed by Tony Gardner, and created by Alterian, Inc. The video was inspired by drummer Taylor Hawkins lamenting having to do promotional work for the song and album cycle while the band was beginning to look older; when Grohl told him that "it does n't really matter", Hawkins proposed taking it in the opposite direction, and purposefully making themselves look older, inspiring Grohl to write up a treatment for the video.

Question: who is the old guy in foo fighters run video?
Steam of consciousness below:
The relevant information to answer the above question is: The video features the band performing the song in a nursing home (abandoned St Luke's Hospital in Pasadena, CA), in make-up making them appear as elderly versions of themselves, and end up inciting a riot amongst other patients and orderlies.
So, the answer is the band.