Even though Lindsay Lohan is currently in Promises rehab, plans for her 21st birthday bash on July 2 at Pure Nightclub Caesars Palace in Las Vegas are still going ahead as planned. But her father, Michael Lohan, is furious about the impending party. "If Lindsay heads to Vegas for a big party when she's released from Promises, it has disaster written all over it," he tells In Touch exclusively. "Why would you put someone who's just gotten out of a 30-day rehab program into a situation like that?" At least Michael isn't a total party pooper. "I understand turning 21 is a big deal. But she can always celebrate her birthday at another time or in another way," he says.