You are not required to ignore the obvious, Ana. If you would have a discussion about career path with ANY student you felt was not committed or a good match to the field, it is not inappropriate to have a talk with a student with a disability. But the focus should be on what they will do (and need to do) and not on the disability. Rather than, "you seem to be having a great deal of difficulty with your concentration and focus", try "the field you have chosen requires tremendous attention to detail and consistency. Do you think that will be a problem?" You take it from there...