I believe that it is Alvor's son that you help escape from being executed at the beginning of the game. Once you exit the cave system into skyrim, you can accompany him to Riverwood or you can leave him and go off on your own.

In one video the player goes with the son into riverwood where he is introduced to Alvor and they go inside their house to talk and discuss the events that had just unfolded.

In another video the player goes off on his own, ending up in Riverwood and meets Alvor on his own for the first time. What I thought was cool though was that the son still makes it to town but does not introduce you at all. The player missed some cool dialogue but gained some other dialogue.

I thought the differences were really cool. Showing off the radiant A.I

it's not alvor that helps you escape

Uncle, good try though