Naya Rivera's father on final FaceTime call with his daughter 'It was just heartbreaking'

Naya Rivera was zipping around in a rented pontoon boat on a lake outside of Los Angeles with her young son Josey on the afternoon of July 8 when she reached out to her dad - George Rivera - with a FaceTime call, looking for a bit of advice. "She would always bounce stuff off me," George, 64, tells PEOPLE in an exclusive interview for this week's issue. "And she wanted to go swimming with Josey out in the middle of the lake."