I would think the certificate 2 in cabin crew is a considerable waste of $5000 - I will happily pass on the information for 1/5 of that amount!
In all seriousness, I personally don't believe a person can be 'groomed' to become cabin crew - you are either the person for it or you are not - and depending on the life skills and experience your girlfriend has I am sure she will be just fine.
The height limit though can be an issue and I strongly recommend she researches that with each individual airline - if you are not tall enough to be able to reach overhead emergency equipment then you are highly unlikely to get past round 1 of recruitment...
Good luck to her!
