I'm certain her boyfriend is contributing to what is likely a natural reaction to being away from home for the first time, but I agree with your instinct to not bring him up. Her desire to come home is normal, but if he was not there, I'm certain someone else would be filling that void like close friends instead. Bottom line: He is likely not THE reason, so I would stray from that even being a bone of contention and focus on keeping her spirits up. Remind her how hard she worked to have this opportunity and that staying the course is where she will find the rewards for that dedication. And let her know it IS okay to feel that way, but in time that will pass. Accentuate the positive and tell her you're standing right there with her and she will see through this bump in the road to better days.