For the OP. Just curious. You said your brother flew just over tree tops so you knew his altitude. And the flights in question are below 500' AGL. You have references to structures to determine the alt of the planes in question. But you have...
That was my thought, some other influence, Karen, Kid, or Unofficial Drone Police. He was obviously well above any obstacles in the area, over an intersection as you could see ahead of his flight path where the incident took place. Rare bird...
I may be wrong, but I believe in past posts here and in other groups it was mentioned that the MAS props although providing better and quieter performance, are more brittle and will shatter if encountering a situation like above. Where the OEM...