I said exactly the same a couple of threads back - that I didn't find it strange that, after making plans to get up at 6.30am, that Dylan decided to go back to sleep. My 16 year old does it all the time - arranges to go out with friends early, sets alarms, asks me to wake him up etc ..... then when the time comes, he says it doesn't matter, rolls over and goes back to sleep! And he doesn't bother to let them know either. Seriously, he is a nightmare for letting his mates down in exactly the same scenario as we have here.
So, I don't find it odd, and at the time of my post on the subject, I did say that ER was actually backing up MR's story when she was saying how Dylan hated mornings ... and she said this AFTER Dylan went missing, when all the other things she said were not in MR's favour.