He said that his Loki betrayed Asgard. Beyond that I did not ask for details.

[He didn't want to know. He'd rather not hear about any version of his brother being so beyond reason that he would destroy Asgard. Because that could never happen. Not with his Loki anyway. (De-ni-al.)]

Apparently it was all part of Odin's plan, to have them become mortal and bring the stories of Asgard back to life on Midgard.

[He sounds extremely skeptical. That's kind of a crazy plan, even for Odin.]