I would show her this recent post for example: Her family will also be thinking about this and will talk to you about it when you spend time with them. I hate to say it, but I don't see this ending well. We always went every Sunday, had family prayer and scripture reading, etc. Dont aggressively try to destroy her faith but bring up philosophical thinking points. To them, everyone is either TBM, hasn't learned the truth yet, or has some kind of personal failing laziness, desire to sin, allowed themself to be deceived by satan, etc. And depending on his views of the Sabbath, you will probably get the tug of war on Sundays. We need to believe fully and then we make choices, not the other way around. There is much that needs to change and many hearts to educate but if we doubt some of the fundamentals then why not all of them. It all depends on the girl.
They're hidden pretty deep on LDS. If you try to deconvert her I suggest indirectly at first. At what age do you baptize. He doesn't realize that when he spends so much time at the hospital they take this as a sign that he has no home life. Thirty years ago I converted a guy and then dumped him for a returned missionary from an established LDS family. He often tells me how happy he is to return to a clean home, warm meal, and me in the doorway-and I think that makes residency all the more bearable for him. In areas with lots of single Mormons of dating and marriageable age, the Church has established singles wards. Most couples who are married where one is a Mormon and the other isn't, usually stems from a situation where they both were married in the temple, then one of them lost their faith sometime after that. I don't think I could let that happen.
Also, they are encouraged to date in groups and not pair off alone, so if your date insists on the same, then agree politely. I have done it many times and the repercussions are that they treat me very poorly, but th. I don't mind staying home because I understand he's tired. I currently just started dating someone who is not only in the military, but a doctor.
It is an act of faith. If she identifies as a Mormon, then she probably takes her faith seriously, and it means a lot to her. Mormon decried it was all a lie, an anti mormon lie.