No, they'll just undock it and send it down unmanned, replacing it with an unmanned Dragon or Soyuz or something. This isn't any real emergency, it's just more bad news piling into Boeing at a time when they can't seem to do anything right
There is also a SpaceX dragon capsule currently docked to the ISS. That seats four. 8 people in space on the ISS right now. Maybe there's enough space with suits on, but I can't imagine there's much leg room for that road trip.
The Dragon in question is kitted for 3. There's also an emergency evac capsule (Still a Soyuz I think EDIT: Yes, Soyuz MS-25!). But that's only another 2-3 and having US astronauts brought back by Roscosmos would be.....embarassing.
Have them touch down and recovered by a Russian crew, give them a massive welcome home and "mission accomplished" parade in Moscow before returning them to the U.S.
The article says the 45 day window is due to fuel limitations with Starliner, so at that point I'd imagine they'd un-dock it and de-orbit without crew. Regardless they wouldn't leave the astronauts to die (I hope) and would mount a rescue mission.