Can you shift your routine around so you go outside at that time of the day?

A 4 year old who cries over toys? That seems very wrong to me. My little ones are cured of crying over toys before they are 2, but this boy hasn't been in your care so the caregiver before you and the parents are the ones who dropped the ball. But I'd be talking to the parents now and getting them to help you put a stop to that. Does he have a nap? He should be refreshed at the end of the day from quiet or naptime, but it sounds like he is overtired maybe?