In Kansai they use "uchi" to mean "me". So "uchi no tomodachi" is "my friend" there. Elsewhere it usually refers to your whole household, like kids might say "uchi no okaasan" instead of the more adult "haha". You can shorten it to "chi" after stuff like "tonari no obasan no chi" - "the lady next door's place."
I think your version sounds like the former usage. Could be wrong though. It might well depend on context. Still I have my doubts. For me the friend doesn't BELONG enough to the family to use "uchi" that way. Family friend would be 家族みんなの友人 (kazoku minna no yuujin) literally.
Here is a random quote from Google: 今日はうちとうちの友達二人で店を任されている日だから... (Today was the day that me and my friend were left to run the shop, so...)