After Sunny leaves Holden’s room, whom does he begin talking to?

Sunny, the young prostitute, goes to Holden's hotel room twice. The first time, she tries to overcharge him, but he refuses to pay more. Later, she returns with Maurice, and they rob him.
In the interval of time in between, Holden feels depressed. He has been up almost all night. He starts talking out loud to his dead brother, Allie. He has a recurring memory of an incident when they were younger—one time in Maine when he would not let Allie go bike riding with him and his friend Bobby Fallon because Allie "was a child." That night, as he often does when he gets depressed, Holden imagines telling Allie to get his bike and meet him in front of Bobby Fallon's house.