Help with DME and split stay off property?

[addiedisney]

Here is the situation. My parents have two nights at BLT then my mom comes to stay with us at the GF while my dad goes off property for a convention. On the last day of our trip my Dad will come back and meet us at the parks before they fly out that night.

Here is my question.....
Because they are booked at BLT for only two nights does that mean that DME will not take them back to the airport after their "check out date?"

My mom is on our reservation at GF so she could take DME, no problem, it's just my Dad I'm worried about. Any advice?

Thanks!
Addie