Who is your dad:
x Jarod Kushner
x Donald Trump, Jr.
x James Mattis
x Steven Mnuchin
x Jeff Sessions
x Mike Pompeo
x Michael Flynn
x Other
Too many things here don't pass the smell test.
- Big companies, government agencies, and schools almost all manage their devices via a central server. They can unlock it/reset it themselves.
- Smaller companies/smaller schools still manage their devices, using Apple Configurator 2. They have to plug the device in to a computer via USB, which is less convenient. But if managed, it can be unlocked/reset if it is being managed.
Without the above, it would take a lot of unnecessary labor to maintain a bunch of devices.
You have the receipt? Really? So your dad went to purchasing and they produced a receipt for them? For this iPad and 999 more?
Contact IT. They will take care of it.
The ex-employee would probably be violating the law, or at least agency policy, to give out the password to anybody, even an employee who "inherited" the device. I don't blame him for not giving the password. He is doing the right thing. Heck, even if somebody in IT asked for the password, I would question it, and insist that they get permission from my supervisor. IT shouldn't need the password. If they ask for it, there is something fishy.