You could try contacting them. Here is their website. Off to the right they have a phone number & e-mail address.
Do you know if Donald was born with the surname LaVaque? Otherwise, you could ask them to look for a Donald with mother Daisy LaVaque circa time of his birth. I don't think families waited too long to have a child baptized back in those times. Hopefully there is not a restriction on his birth year. But if there is, maybe they will make an exception because he is deceased. Also, have you tried to look for a birth record? Maybe Gertrude didn't have it destroyed? Good luck. RP.
Phone: (715) 423-1351