This will not be easy to do. Clearly these lyrics are 'heart-felt' which means you will have to be careful not to hurt her feelings if you try to advise her. The first 2 lines really set the tone and I think most people would find it over-stated and 'over-blown'. I don't know how you could suggest the lyrics should be more subtle and less specific,for example more enigmatic - which leaves more to the listner's imagination and allows room for some 'mystery'. In fact, maybe you can't say anything at all about the lyrics themselves without upsetting her. Maybe it's best just to come up with a chord progression that will 'fit' (if you can) and not even get into a discussion of the lyrics at all.
I'm certainly no expert, but I just get the feeling that you have to tread carefully - this is a potential mine-field - for her as well as you. Good luck
One good thing about music is that when it hits you, you feel no pain - Bob Marley