I'm sorry that your family id going through such a tough time,

But you need to just stop, don't check her phone , don't ask if she is doing XYZ .. really that is between your parents. Of course it's upsetting to you. But it is not your business or place to get in the middle of it.

I hope things can be worked out with your parents and if not, Life will go on , you'll grow up and start your own family.

Take care