Sure friend, hope that helps. That’s gotta be a total bummer for your girlfriend.
The point is that you can get an IEM that is close, then use the techniques I mentioned to further tweak it until she’s happy with the results. It’s definitely going to require a bit of tweaking, because as mentioned above, manufacturers don’t intentionally put out headphones/earphones with no treble.
Also consider earbuds as option. Since they don’t seal in the ear canal, a lot of energy is lost that would otherwise be blasting her eardrum. Same rules apply though - stay away from drivers that have diaphragms of graphene, titanium, and beryllium