Through his peripheral's she noticed he had turned to look at her and she turned to meet him. His reaction was strange, unfortunately for her, no matter what information her internal database held on emotions and facial gestures, without knowing the guy she couldn't figure him out. Her mind was searching eventually reaching a conclusion, the best way to deal with unknown gestures was a neutral one in return. She gave him a weak smile.

"I'm sorry for your loss. May I ask how he died?"

Again, an unconventional question to mutter in front of a grave but Cortana couldn't console the guy if she didn't know what had happened. She was also curious.