I find they take a bit longer to adapt to being outside. It is overwhelming with the new environment, sounds and all that. All you can do is wait him out while trying to keep him involved in the activities. I find it also takes them longer to realize they can be mobile in the grass...so if he is not yet fully mobile inside it takes longer and may be upsetting him even more.

As for the am snack. Can you ask the family to feed him earlier (or later)? See if that will help him either accept snack or last through until lunch time?