Interesting question and situation once again, Kaloes!
I would say " A " also, "Disregard his words and help him with the burial of the town people.
It might be a bit difficult not to chose " B ", as sometimes a person's instinct may be to go and try to find safety somewhere no matter what, but is there really any place safety can be found?
Thoul had a good point about perhaps the people that did this would not come back as they thought everyone was dead, etc. Then again, they may indeed come back to make absolutely sure. However, there is no guarantee that you won't run into them somewhere out there while you are on your own either.
I can understand the decision to perhaps split up, but I think there may be greater safety (and possibility of victory if facing them again) to stay together in these types of situations.
Also, if the friend is very distraught, he may need someone with him also to make sure that he won't do harm to his own self for whatever reason. Or just give him support, etc. to help him make it through this tragic situation also.
Also, these people were family, friends, and neighbors, of both of these youths, so both of them should stay and help in the burials, searches, rebuilding, etc.