The whole story start off as an accident. At the beginning, we bought some sweet potato and mean to cook them, but we forgot one at the bottom of a chair and next time we discover it, there were green leaves growing from it. So we put the sweet potato where it can access sunlight and leave it there (and foolishly assume it'll take care itself). After a period of time the sweet potato look like the following photo now.
I've tried to ask my friends and google whether if it caught a disease or something, but no one is entirely sure if it is still alive. Since there's still one or two green branch and leaves on it, I wonder if it can still be saved? And if there is still hope what action should I take to save it (I live in an small apartment in a city so putting it in the backyard is not possible, I've read some other question that it is possible to grow them in a big bucket, but I would like to know before stuffing it into the soil in a bucket should I do something first)?