If she is worried about these thing then she should talk to him about it and ask him if they are the friends or more. He may be wondering the same thing it's always good another ways to start out as friends and then allow it to develop into more on it's own. What you have to do is talk to your daughter and tell her that she shouldn't feel as though she doesn't deserve to be happy have a nice and cute guy like her, right now she doesn't know her self worth and what she deserves so she is and will be questioning when any cute or nice guys pursues her and she has to get out of that negative opinion of herself. Only when she can do that will she be able to relax and enjoy his company without having to put a label on the relationship and questioning his intentions. If you have more to add just click reply instead of openign another question it will be much easier for you.
I think he just got too drunk and slept it off most of the day yesterday I would wait to see if she hears from him today. I really doubt he would purposely turn it off to only her if he made such an effort to see her before he left. I think he got with old friends and spent time with them and got a little drunk but I don't think she has anything to worry about she may hear from him today, tell her not to be upset with him for not calling that will sound clingy and she doesn't want to do that already, even if she is mad tell her not to let it show when or if she talks to him today. He may have also turned his phone off while he was drunk and doesn't know that he did so. Tell her to give him until the end of the day to call and if he doesn't call today then it could be that he is just having fun seeing old friends and family and don't take it the wrong way. She needs to be patient and calm about this so not to blow this.
She is going to have to try and gradually trust in him he hasn't done anything yet to show her that she cannot trust him and she doesn't want to blow a possible good thing. Trust isn't going to be easy to come by especially with everything she has been through with relationships. One thing she can do when she starts to think negative is listen to music and take a calming bath if she can but also she can meditate also meditation can be very soothing like some short breathing exercises to calm her down so that she doesn't panic into thinking the worst. After a relationship ends one of the most difficult challenges is to learn to trust again. The only way to end the trust issues and reclaim her life is to effectively "erase" the memory of the past from your mind and heart once and for all! This will not only open her heart to love but make it so she can have a healthy relationship without thinking it's going to end even before it's really started She has to regain her confidence, courage, self worth, strength, to feel complete able to trust so she has to work on those issues along with trying to get trust back.