Planet13 - 4:53 pm on Dec 31, 2011 (gmt 0)
What type of links are they?
I mean, when I hear the words "million links over a couple of weeks" and the words "1 million links on a single keyword" I think that site is going to get an over optimization / -950 / goodbye to being indexed penalty.
I think that quite simply you should tell them the truth: That the person who did the SEO did something incredibly risky and that they will probably lose all rankings (if they even have any now). You should also mention that some sites when penalized by google for link building have taken over a YEAR before they are allowed to rank for anything in google.
Sorry I don't have better news.