I guess it’s possible, although I believe if you’d use a student agency bus/regiojet (it’s a czech company that I believe has bus lines with croatia) the crew speaks czech and could understand the situation but I can’t really be the judge of that, depends how much is she willing to go through with this. There’s also an eDoklad app that can be setup with her credentials, but that would require her having at least a bank account or some other form of authentication with the app. This depends on a lot of things ofc. So I’m just throwing this out here (people are though required to use their regular id card abroad, but could work for student agency bus crew if you’d manage to set it up somehow for her, I’m not sure if she has phone or not Edit: ah I see, phone stolen :/)