I've had a friend similar to yours, yeah you can encourage them to eat but don't make them feel to bad about it. Just try to be there for them because there might be a reason behind why she isn't eating, you should maybe ask her about it. If it gets really serious you should go to an adult.
Life was cool to me but, now it's not so good cause of the Corona virus, so now I can only go to soccer practice and come back thats all I can go. So I hate life now.