"Why did you the two of you have to go that far just to end that guy's life?" Marcus asks in a concerning tone. He knew what the organization is teaching them is not all good, but it's a bit concerning if his grandchildren would go that far just to kill Juan at the age they are in.
"Are angry at us that Juan is not breathing anymore?" Aaron is somewhat curious to know if his grandfather feels angry or sad at the fact that Juan is not alive anymore. If his grandfather is sad, then he guesses that he wouldn't blame his grandfather to feel that way since his grandfather did take Juan under his care for so many years.
It would not be a surprise if Marcus cared for Juan.