Unless you're living under a rock, I doubt very seriously that anyone hasn't heard of Trump's disgusting hot mic talk about women. I don't think apologies are going to work and any fence sitters have probably shifted to Hillary because they had to be offended by his comments. He should quit. But, if he does, I seriously think Hillary would be in trouble. Anyone else that the Republicans could come up with could beat her. That's because, as terrible a candidate that Trump is, she is struggling to maintain a lead. Hillary should pray that Trump doesn't quit.
Reference: Trump recorded having extremely lewd conversation about women in 2005: https://www.washingtonpost.com/politics/trump-recorded-having-extremely-lewd-conversation-about-women-in-2005/2016/10/07/3b9ce776-8cb4-11e6-bf8a-3d26847eeed4_story.html