Two choices...First off I would be home the next time he comes over to greet him at the door. See how he pulls up...it could be an isolated incindence.
1) Speak calmly and rationally to him and present the issue with plenty of caviats. (just a diplomatic opinion...I deal with powertripped assholes daily...I work for one) And talk it through.

2) Tell your wife's friend that someone else can watch their child.
-cbx