Coming from a girl here. It sounds to be this girl has a huge crush on this friend of your's. If she is getting vulshy with you and getting defensive if you ask about what she's up to.
The best thing you can do is to back off and leave her be. It sounds like she is really into this guy she is texting all day and mimicking the stuff he is into to catch his attention.
I get the fact that it makes it kind of hard because you two have a history and from what I read I get the impression you still have feelings for her. Speaking out of kindness here and to save lots of heartache, let her follow her heart.
"If you truly love someone, you would let them go and be happy, that way if they come back to you then it proves you are meant to be."
The best thing you can do is to back off and leave her be. It sounds like she is really into this guy she is texting all day and mimicking the stuff he is into to catch his attention.
I get the fact that it makes it kind of hard because you two have a history and from what I read I get the impression you still have feelings for her. Speaking out of kindness here and to save lots of heartache, let her follow her heart.
"If you truly love someone, you would let them go and be happy, that way if they come back to you then it proves you are meant to be."