What is a parent to do?

Ah!! At last!! School holidays are over. Three weeks of what are we doing today? Where can we go? Give us some money!! I need to buy... Mommy, I'm soooooooo bored!!! But alas, that also means that my two older children returned home to their dad. Not without some complications I might add. My 12 year old daughter refused to return. She wants to stay with me. Again. She is unfortunately in Grade 7. Here is SA, that is the grade before the start of High School. I couldn't allow her to remain here and then try to find a school where she can complete her Grade and still be accepted in a High School next year. Very very very reluctantly and crying profusely, I escorted her to the security check point at the airport and her brother helped her further along onto the plane. It was the hardest thing I have ever done. To stand there and watch my child sobbing, begging and pleading. I got an sms from her saying that she is not strong enough to last until the end of the year. That was the compromise. She may return, but only after she completed her grade. She is a very clever girl. She has worked so hard this year and I didn't want her to give that up. I feel so helpless. I wanted to call her back from the plane. I wanted to hold her and tell her that she may stay. When I reached my car in the parking area, I sobbed. I cried all the way home and then I received a message from her saying that she just can't do it. That 5 months is too long. That she doesn't have the strength to see it through. What to do? What to do? Do I just leave her there and tell her to buck up and chin up and just be strong or do I fetch her? What about her brother? Although he is older than her, what would it do to him to have her living here again and him in Pretoria? What if she is here again and after 6 months decides she misses her dad and wants to go back to him again? Why do I say again? She has done this before. In the end, I want to do what is in her best interest. She is reaching the age where a girl should have her mother around.