Granny Smith finds her daughter-in-law collapsed and mortally wounded just outside the farm.

There have been many theories on how the Apple sibling's parents died. It's heavily implied that they both passed away, but it is never made clear as to how they went. Obviously seeing as MLP is aimed at younger audiences, there is but so much that they can say about it despite the fact that other animated shows have tackled the subject of death (It really all depends on said shows and what risks they are willing to take). But in the case of this series all we can really do is speculate or theorize, and this is my take on what happened.

As I see it, Bright Mac and Pear Butter's lives were cut short due to a tragic accident. The two were on a delivery to a far off town, taking a dangerous path to get there. But en route, they were attacked by a pack of timberwolves. Bright Mac was killed defending his wife and while Pear Butter managed to get away and back to the farm, her wounds were too deep and she collapsed to the ground, where she promptly died. Granny Smith found her that morning and got her some medical attention, but by then it was too late.

Pretty gruesome I know, but in a situation where both parents are gone, realistically this is how I could see it going down.