I have this issue quite often in role plays (in-game) where one of the other players is sitting a distance away from everyone else making posts such as: posts about how sad they are, or how they sit there thinking to themselves, doing nothing at all that could attract the attention of any of the other characters.
Whom, of which this players character is usually not acquaintanced with any of the other characters, whom are likely already having a conversation of sorts.
And just sad things in general give me a hard time. I've never known what to say, let alone where to start, to be of any comfort. Unless, perhaps I witnessed just what the other is sad about.