Xiao Bai Tu - special interviw situation need your help

Dear Xiao Bai Tu
My mother had been rejected for non-imigrating visa for many times. The last time she applied was 5 years ago, with the "help" from so-called "visa service " in Shanghai, she wrote down she was re-married, even though she has been a widow ever since my father passed away. She was rejected at that time. Last year, after I got my citizenship, I petitioned imigration visa for her, and in the application I indicated that she was a widow and only had one marriage. And the application was approved and she got a interview notice from GuangZhou recently. Now what should she do? Will VO compare her documents to her old records which had false marital information? Should she admit she lied 5 years ago? Has anyone has similar situation and what's the outcome? Thanks!