EEA NATIONAL AND NON EEA FAMILY MEMBER, PLEASE, URGENT!

Hi all,
My mum is an EEA national (italian citizen). I'm a Non EEA family member. She will go to the UK to live there permanently and i will join her, just for a month, and come back to italy to finish the university b4 i join her finally. In the UK Border Agency website i read she has to write a a cover letter to declare i will join her in the Uk. What does she hast to put in the letter about my dependency? I'm 23 and i'm dependant on her. Please, what good evidences she must show in order to make the letter more convincing? Could you kindly give me some idea of the main points that must be included and is it necessary to refer to the EEA directives 2004 ?

Please, help me out! Thanks alot in advance and I really appreciate your help!

Is ur son an EEA National?

How old is he?

Is he dependant on you?

My son is not an EEA national and he's 23 this month. He's dependents and still studying in the university, but during summer, he works to support himself as well. Would that affect his application for a Non-EEA family permit ? Please, how can i solve it and what other things could hinder him getting the Non-EEA family permit in order to join me in the UK ?

Is he dependant on you?