#kindness

My 4yo is picking up negative behavior from friends. How can I shift this?

It seems that my 4yo son and other friends of the summer camp are getting a kick out of making a little boy upset and keep bothering him because they noticed he easily cries.
I already told my son that it is not okay to bother our friends if they do not want to be bothered.
What do you recommend?

How can I explain to my daughters that they are being mean to others?

When my daughters get together they are extremely silly and have so much fun together. The other day we were also with another friend's daughter who is a bit younger, less verbal, just not as strong of a personality. The girls were giggling hysterically and calling her a poopy head, saying they wouldn't share their food with her, etc...all while laughing hysterically. My friend and I are very sensitive about not wanting "mean girl" daughters so help us understand the difference between being silly and not truly trying to be mean and consciously being unkind which I really don't think they were doing.