C172 Pilot reported observing an aircraft incident while holding short for the runway. The pilot exited the aircraft to provide assistance and then taxied back to parking.

Narrative

After finishing my preflight inspection; I started the airplane and announced on the radio that I would be taxing to runway XY. Along the way there; there were no other aircraft on frequency making radio calls. Once I arrived at the hold short line for runway XX; I looked for traffic and I did not see any aircraft approaching runway XX. No one had made any radio calls; and there was no traffic shown on [my aircraft's] GPS with ADSB. I then announced that I was crossing runway XX at Taxiway 1. After that; I began crossing the runway and as I was clearing the hold short line on the other side of the runway; my instructor called over the radio telling me not to take off; and that there was an emergency aircraft that would be overflying runway XX to circle to runway XY. Shortly after that; the airplane overflew runway XX. I then taxied over to the runup/hold short area of runway XY at Taxiway 2. From there I saw the emergency aircraft circle back around for landing. When they touched down on the runway; the airplane rolled down the runway for a moment then its right landing gear collapsed causing the right wing and nose to hit the ground. The airplane then started sliding on the ground and slid off the right side of the runway after the intersection. From there; I shut down [my aircraft]; engaged the parking brake; and ran over to the crashed airplane to make sure everyone was ok. One of the employees of the airport had also driven over there as well.After confirming that everyone was alright; I went back to [my aircraft] and got on the radio and called the UNICOM for instructions. I was told to taxi back the way I had come and park the airplane. I then started the plane up; announced that I was taxing back to the ramp; and began taxing. Once I got to the hold short line for runway XX; I checked for traffic and then announced that I was crossing the runway at Taxiway 1. Once I was clear of runway XX; I announced that I was clear and taxing the plane back to the ramp for parking.