How do you nurse the sister back to health?

[Mura]

The game is prompting me to do this but I don't know how to do it. How do I go about it?

[Mackenzie]

Wait till the next day and you should see the option when talking to her.

There's a bug where if she's at exactly 60 health, you cannot nurse her, but yet she is in sick state.

Can nurse her at 59 or lower and she is not sick at 61 or higher.