cabin crew recruitment
Whatever you do don't pay for your grandaughter to attend one of the training courses. It would be more helpful to have the college course that she is attending with her languages and maybe some working experience within the service industry dealing with the public on her cv rather than the above said course.
Most airlines tend not to recruit crew under the age of 19 with a few exceptions, and certainly not under the age of 18.
My advice would be to gain some service experience and when she has reached an age where she can apply to the majority of airlines she needs to write to all of them specifying her interest. The airline industry usually recruit new crew between November and March ready for the busy summer season.
Most airprots have an airport job centre where cabin crew posts are advertised, these can also be accessed via the web.
There is no right or wrong way to get through an airline group interview selection. All airlines are looking for different things.Just be yourself, look smart, be on time, work as a team during the interview tasks, listen to the other applicants opinions as well as adding your own. Most of all be confident! they do not like loud and cocky or quiet and mouselike.
Good luck!!