I don't think they can deny him his seat because there is no positive evidence that can be proven in a court of law. He said, she said is all they have. In Franken's case, they have photo's and his statements about wanting to rape Leslie Stahl after drugging her and taking pictures. Its all coming out.If Moore wins, I don't think the Senate will allow him to be seated, or will vote to oust him (I'm nor sure of the procedures)
The Republican establishment does not want Moore in office because he will side with President Trump and be a thorn in their side. That is why they were the first to come out to dump him.