Lorka

My aunt and her two children are selected for further processing for the dv-lottery 2012. Last year when she applied, her son was 20 years old (he is 21 now) and I think he is eligible to go to US with his mother but at the moment he is living in another country, in western Europe and the lawyer there has promised him that he will have his permanent papers pretty soon. Meanwhile my aunt has to fill out form ds-230 for both of her children. Her son doesn't want to risk and go to his home country because he says what if they don't get the visa! My question is: Should my aunt fill out form ds-230 for her son if he doesn't want to go or no? When she goes to the interview at the embassy is it going to be a problem that her son is not going to be there because when she applied for dv-lottery she entered her son's name also? Does she need to show any proof to the embassy that her son is not living in his home country? Can somebody help me please with these questions? Thank you!