Why does Gail want to go with Wes when he talks with Marie?

Gail offers to go with Wes, saying that Marie will be more comfortable with her there, but Wesley says no and that Marie’s comfort isn’t what’s important at the moment. Gail persists, but Wesley refuses, and David realizes his father doesn’t want his mother around when he’s interviewing Marie. He wonders if his father is trying to protect his mother from the ugly truth, or if he’s trying to protect his brother by keeping the number of witnesses to a minimum.