What? At most fraternity parties the door is unlocked so anyone can enter or leave. There is no indication they were being held against their will- no one, the father or police claimed this. Letting them enter the frat house and then refusing to give them a ride is not kidnapping. That is ridiculous.
Suppose they were told they were going to a Beanie Baby swap meet and instead were taken to a broken-down dive full of drunken frat boys and then were told to fend for themselves? More information is needed to make a judgement.
In this state he could have started firing and killed every single one of them and walked away free.