I would get YOU out of it... your wife is going to turn YOU into a target if YOU are in that...
The idea I thought was for this to be OMW saying her brother is behind this?
Why are you there? Just step out of it or your wife is gonna blame you... let the call happen, but stay out of it if you can... Or at least in the call emphasize you haven't called for 7 weeks or whatever and that you aren't going to your wife's work or anything... plead innocense to following and watching or she will target you.
If OMW Brother is willing to take the hit let it go that route...