The jury is undecided on this issue, other than it being a known P4 issue that has effected many others recently as well. So, the good news is that there is very likely nothing with your specific copter, and we are hoping that it is a software or firmware glitch that will be addressed in a future update. What your dad did is correct. Land and reboot...
Many folks panic - understandably - when this occurs due to what they see on the screen, and it appears that your dad kept his head about him. Good job!