I saw myself in the third person, but experienced the dream in the first person, so I will write the dream as such. He = me.

My mother was perched some 15 meters up on a tree in the neighborhood. He needed to give some her keys, so he threw them up the tree, but he missed. My mother, in an attempt to reach for the keys, lost her grip and fell down. When she landed I expected her to die, but she got up and stumbled. I was relieved that she was alive but very concerned and vaguely guilty about missing my aim. He went up to her and instructed her to lie down. He would call an ambulance.