It could be fraudulent conveyance, which is when you give stuff to friends or family members in an attempt to avoid paying a creditor. Giuliani's son claims they were a gift like 6 years ago but that's contradicted by Rudy's own previous filings, expert lawyer that he is.
I'm no lawyer but my guess is that the court tells him to fuck off and turn them over as most property is not protected from seizure other than your home and your car (and sometimes not even them). I guess we'll see!