My paternal grandmother was a JW, and she asked my parents to make sure she had a JW funeral....so, when she died, the arrangements were made, and there was a memorial at the KH for her, which was well attended. My father's sister, was very upset, she refused to go to the KH for the memorial, but instead had an Anglican service for her about a month later. If your father is not a JW, then I'd definitely ask him what he'd like, and go for it.. the JW's here are only too happy to take over and hopefully get some kind of a donation out of it...even if the person being remembered was not a member....they do it for the family members who are in "good standing".
Delilah