He just sold out
She probably has to do some unspeakable act with and to Trump to keep her crown.
No he is doing this as a business decision.
If he boots her she goes out of the pagent program and goes into the paris hilton for hire path of 15 minutes of fame.
He gets to keep her, gets to use the ensuing PR curiosity, and now he has leverage.
I bet she consents to a chaparone.
(I suspect much of the purient stuff in the press beyond the drinking and the drug test was more wishful thinking than fact. If there was more there would have been pictures.)