A lad up the road from me has just got into this years TUI apprenticeship scheme and is over the moon about it, he has almost zero aircraft engineering knowledge but got selected. I believe these days they are looking for basic behaviour and personality traits first, be positive, show enthusiasm for the scheme and just have a cool head on young shoulders. I went thru with him roughly what the scheme would be about, I explained how he would be trained and how to gain the engineer licences, very basic aerodynamics, jet engine theory and aircraft structure but I feel his enthusiasm and mature, inquisitive mind are what got him in.
Do some study on the company, know some basics about the history of the company, number of employees, where are the factories, where is the HQ etc
Hope all goes well with your lad.