Approved I-140, company sold what now?

[Bridgett]

Hi.  I am trying to help my brother-in-law (BIL) understand this process.  I was successful in obtaining a green card and ultimately citizenship for his brother and want to desperately help my BIL.  He has an approved I-140 (priority date of 2005), receipt date of 2007.  He is in Category E3.  His company was sold after the approval BUT he continues to perform the same exact job duties as he previously did with his old employer.  

We are going to meet with an attorney about this in a few weeks but I want to know if we can use his approved I-140 from the previous employer by trying to prove successor-in-interest or is there a way to amend the I-140?  Or is it just best to refile the I-140 with a new labor cert?

Any help is greatly appreciated.