R.,
My brother and his wife had a bat in their house early this summer. My 2 year old nephew woke up screaming, and thats when the found the bat.
They called the pediatrician just to talk about it and he recommended that they ALL get rabies shots (which they have done - no fun!) The recommendation is if you wake and have a bat in your room that you should assume you were bitten and do preventative shots. Apparently bat bites are very hard to see because they are small, and you wouldn't be able to tell if you had been bitten.
My brother lives in Hubbard County (northern MN) and a man died of rabies there last year because he didn't realize he had been bitten.
I'm sure that is not what you wanted to hear, but I think better safe than sorry. I would say the Dad should have to have the shots, and I'm surprised that they haven't had a public health official involved. Can you contact public health in his area? If they have small children of their own, it is a risk to them if bats are coming in.
J.