I don't know the scene in Montréal intimately, but it sounds like she's interviewing with digital agencies who are keen to hire app designers.
If she's eager to move into UX design, perhaps applying for agencies that are after someone with mobile app experience is not the best move. If the feedback is that she doesn't have a "UX mobile portfolio" then I'd question whether the employer is actually looking for a UX designer, or even understand what value a UX designer brings from earlier stages in the design process. It honestly sounds like they're hiring for a UI designer.
One thing they are correct in asserting is that focussing on her responsive design experience isn't enough to find a job that is not just designing more responsive layouts. I'd suggest that she needs to tell more of a story in her portfolio, and talk about what other parts of the process she has been involved in—strategy, research, ideation, testing—and what measurable results her designs were able to achieve for the business. This way, she can demonstrate real value, and better communicate her thought process to employers.
Also, if she's lacking mobile app experience, she should design her own or approach a non-profit to help with their project. We talk about this a lot in our Get Started in UX book.
The final piece of advice I'd give her is to join these forums herself! We'd love to help more if we're able to.
Hope that's all useful.