How can I resolve FaceTime video issues with Screenplay?

My friend and I both have recent iPads (last two years) and are updated. When we FaceTime all is well, but when I go to screenplay a movie, it works, but it won’t show the video square while watching the movie. The smart audio works but we can’t see each other. When I try this with other friends it works fine. What settings on his iPad need to be changed? Help!

[Re-Titled by Moderator]