They didn't have a lease. They had, at best, an agreement with SAE to live in the frat house for a specified rent. SAE has disbanded the chapter so really they have no agreement with anyone and the university wants its property back.
And it's not like they're on the street. The university has said that they can contact the Dean of Students if they need special arrangements for housing.
That, least under the torturous California law, is established residency which requires formal eviction to force someone to leave. Don't know Oklahoma law, but suspect that every hotel in Oklahoma carries a notice that rooms may not be rented for more than 30 days in a row to prevent establishment of residency.
And it's not like they're on the street. The university has said that they can contact the Dean of Students if they need special arrangements for housing.
Then I wonder who at the university made the statement that no aid or assistance would be given to these students, as "we don't help bigots" - it was the tag line for yesterday's NBC Nightly News story.