My friend wants too gain weight, from the photo, should she gain or lose???

Basically, since christmas, she has gained around 25 pounds. All she does is eat junk. She never exercises either. We hang out nearly everyday and she eats way too much. For example we were in Maccies the other day and she ordered a large big mac meal, a double cheeseburger and a mcflurry. Ate it. Then within an hour, went and got another double cheeseburger and fries!

But a few days ago she came too me and explained why she was gaining weight. She said she wants too weigh 12 and a half stone. She said she is bored of being skinny and wants too be chubby :/

She is 16

5ft 5

and currently weighs 11 stone 7 pounds

She is a naturally skinny girl but carries alot of excess fat mostly on her stomach and hips. This isnt me being a penis either, she wanted me to do this so she could see if its sensible too gain anymore weight. Or if she should lose some.

Personally I think she needs to lose alot of weight

So basically

Should she lose or gain weight?
Is she overweight already?
What can she do?
Advice on what she should do?