Hold it right there, outlaw! This article is littered with spoilers, so I reckon you might ought'a mosey on down the road if you don't want to read any plot details.
Remember My Family is a Strangerside-mission, the epilogue of Red Dead Redemption and the only mission which can only be done with Jack Marston as the protagonist. It is classed as a Stranger side-mission due to the "?" shown on the map, but technically acts as the final mission of the main storyline.
The mission will start when the player talks to Agent Howard Sawicki in Blackwater, indicated by the "?" on the map — the train station on the west side of town. The agent will point the player to the south of Lake Don Julio, and the newspaper includes a story about how Edgar is now living near the lake. When the player arrives, only Ross's wife is present, and she says that Edgar went with his brother on a duck-hunting trip down in Mexico.
In Mexico, close to the river, the player will find Edgar's brother, Phillip Ross, at a campsite. He points the player down along the riverbank towards Ross. Down the riverbank, the player will encounter Edgar Ross, who, after a short chat, will challenge Jack to a duel. If the player wins, Edgar stumbles backwards and falls to the ground, dead. Jack looks down at the gun he just killed Ross with. Without knowing it, he has just thrown himself into a life of violence his father died to protect him from, but at the same time has redeemed his father's honor by killing his killer. He walks away, the camera zooms on his face, and the screen is tinted red & black with the title Red Dead Redemption, and then the credits roll.
If the player wants to get complete and total revenge you can kill all of his family members, his brother and his wife. Doing so will result in negative honor (unless if you have the bandana on), but killing Ross will restore the honor lost. After the credits finish, walk over to where Ross's body is and loot it (he should have around 400 dollars on him) for money and luck increasers.
For this duel, targeting Edgar in a lethal manner is required. If the player attempts to target the gun or arm of the target (normally a disabling shot), the duel will be lost (the bar will simply not fill when targeting his hands; this happens in other important duels also). This will result in the player's death and then the player must retry the duel until a fatal shot is achieved.
Attempting to snipe Edgar prior to the duel will result in an automatic mission failure; simply looking at him through the scope will trigger this, even before you try to pull the trigger. The same goes for Edgar's wife and brother in the earlier step.
The player can use this mission to acquire the Semi-auto Shotgun for free; simply fail the duel until Ross has the Semi-auto Shotgun equipped, then kill him and loot the gun.
While confronting Ross, Jack mentions that he saw him kill John, despite only hearing gunshots from a distance and riding back to the barn only to find a corpse.
Sometimes when you are dueling Ross he will be facing toward the pond shooting ducks, but can still be killed and he will not fire back.
Sometimes, a glitch will occur in which a second shotgun can be seen floating beside Phillip Ross.
Sometimes, players may experience a glitch where before, during and after the conversation with Ross, the game cycles world elements such as time of day, and weather, as sometimes, if one is to start talking during the day, it will end at night or vice versa. Or if it is sunny, sometimes the weather instantly changes to raining weather.
Listening to Ross's comments before the duel, he can be heard cursing when he misses the shots.