The upcoming SpaceX mission to the ISS was originally going to take a cosmonaut. Perhaps they can leave the seat empty for the stranded NASA astronaut to hitch a ride home.
Good idea but it won’t work as there are 5 astronauts who need to return with 4 returning on the Dragon and the other was suppose to return on a Soyuz.
And while they are up there, change the locks to the ISS and throw all of Russia’s stuff to the curb.