I think attach the cot and get a mate to help move the bed etc. When he sees that the co-sleeping arrangement involves extra space he should come around. Co-sleeping meant we all got better quality sleep (until DD got too big and spread out across the bed forcing DP and I out ). It's a tad stubborn that he won't even look at the setup photos but if he gets a visual it really could sway him or at least might get him used to the idea.

HTH!