Is there any legal action that can be taken against my friends mother?

my friend is 22 and lives with his mother but right now he is over seas for a few months. he asked me to go over to his house and check if he got something specific in the mail as he isn't on good terms with his mother. i went over there and couldn't find anything for a while and then one day decided to look in the garbage and found out that shes been ripping up his mail and throwing it away. ALL of his mail, regardless of what it is. I am wondering is there anything that can be done about this?