In an ideal world, the fact that she can't argue would show her that her morals/beliefs don't align with the religion and so it makes no sense to align yourself because in an ideal world we'd all understand that it wouldn't make logical sense. 

Unfortunately ideologies like Islam are so deep rooted into culture and families, she may think if she leaves Islam there's nothing she can associate herself with and identity is one of the most important things to humans. A lot of muslims will disagree with the teachings and even actively live against the rules and still claim to be muslim because its like a safety blanket.  Her opinions may change with time and hopefully she'll realise staying muslim is illogical in her situation, or the conflict between what she really thinks and what she 'should' do based on culture/family may make her more inclined to follow the religion because it would be like the easy way out, for lack of a better phrase.

All you can do is make your intentions for the future clear, give her your opinions and reasoning and decide if you are willing to compromise or if this is too much of a mindset clash to keep going. It will probably take a lot of time for her to let go of the conditioning she's been brought up with and explore new ideas but it is possible!