Since he's a stranger...
Penny would escort him back to either her home or his (if it was closer), clean him up, then tuck him into bed.
Once comfortable, she'd tell him every story she knew that had a happy ending, for as long as she could. Hopefully, until he fell asleep.
It will likely be a long night, and if he happens to find sleep, it would be better to also have something lighter on the mind, to try and counterbalance the day's tragedy.
Afterwards, she'd sit quietly on the opposite side of the room, likely reading (as it would feel like an inappropriate time to tinker with watches), ready to listen if he needs to talk.