It's frustrating when kids won't sleep during naps and it doesn't help that parents aren't on board,,, I'm in a similar situation - my 14 month old needs to always sleep in his stroller for naps and I've been bringing it inside and rocking him, but no more! Plus he's just come back from a 2 week vacation and is now crying in his playpen,,, I'm putting my foot down and telling mom that it's playpen or nothing and to please help him get on schedule at home by putting him to sleep at around 1pm on weekends,,,, I've worked in centres where the older kids colour or read, but try to see if he'll still nap and if he still refuses, then you get him some quiet nap time activities,,, Good luck!