I-130 is just a petition to file AoS for an immediate relative and has nothing to do with the actual 485 application which is the AoS app. So PD for your 485 will always be connected to your filing of the 485 app.
Your friend can continue the employment based GC app. It's just that when filing out different forms, questions like "have filed for xxx before" have to answered carefully based on where the other applications stand.
HTH
I'm a nobody and nobody's perfect. So I'm perfect.
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DO - Chicago
N400 RD - Sep 14, 2009
N400 PD - Sep 17, 2009
Fingerprinting - Oct 13, 2009
N400 ID - Jan 6, 2010
Oath scheduled - Jan 12, 2010