system
Given the following post, respond as if you're commenting on Reddit:
human
[ASOIAF] How would Tywin, Ned, and Robert react if Jaime tried to stop The Mountain from raping and killing Elia as well as her children? What would have happened to him?
gpt
Robert would be angry, not because he's pro raping and killing babies, but he just wouldn't want to have to deal with the situation. He's a guy who just wants to fight and get laid, not have to get involved in politics. Now he's forced to deal with what to do with Rhaegar's family. If he gives the order to kill them, he's made an enemy of the Martell's. If he spares them, he looks weak. 

Ned might have more respect for Jaime, and would be more likely to hear him out about what happened with the Mad King, and probably doesn't look down on him for being a kingslayer. Depending on how Robert handles it, it could end their friendship if Robert orders them to be killed. This means Ned wouldn't become the hand years later, and the story would change dramatically. It may even put him on the Lannister side if he believes the Joffrey is actually Roberts son, and Stannis and Renly are in the wrong. 

Tywin would be dissapointed in Jaime, and annoyed like Robert at having to deal with this now. The Mountain and Amory Lorch killing them let Tywin show his loyalty to Robert, now he doesn't have that going for him and has to deal with the Martell's wanting the safe return of their Elia and her kids.