Start over at the beginning. Place crates in separate rooms and begin again from there. Especially with 2 pups, siblings I am assuming; they have become to dependent on each other. It will probably be a longer process with Rocko since it appears from what you stated he is the more dependent one.
Play, train separate from each other. Allow only a short period of play and interaction between them each day. Get a trainer involved if you haven't already.