He may not have gone very far from your friend's house, mini-me. Sometimes they're just frightened and hunker down under a porch or in a shed or in thickets nearby. Here's a thread that might be helpful:
Tips to help find your lost cat
Good luck! I hope you're reunited soon!!
"We are--each of us--dying; it's how we live in the meantime that makes the difference."
"It's not what you gather, but what you scatter that tells what kind of life you have lived!"
"Be kinder than necessary, for everyone you meet is fighting some kind of battle."