"He is a high-profile athlete and a star in this league," Conway said. "He did do it or he didn't do it. There are lots of reasons to believe he is getting preferential treatment."
Sterger accused Favre of sending her racy voicemails and naked pictures two years ago when both worked for the New York Jets.
The 41-year-old started for the Vikings in their Monday night game against the Chicago Bears last week and was knocked out early after suffering a concussion. He is listed as doubtful for Tuesday night's game against the Philadelphia Eagles.
The NFL announced last week that they have not come to a conclusion in the investigation.
Earlier in December, Sterger's manager, Phil Reese, said his client wants the investigation to end before the season is over.
Reese said in October that if the league doesn't punish Favre, Sterger might go public with her evidence.
Favre admitted to leaving Sterger voicemails before a Week 7 game against the Green Bay Packers, but denied sending naked photos.