A Freudian slip, perhaps?
When it comes to relatives by marriage, the mother-in-law is most apt to be labeled bothersome, for her meddling, judgmental, demanding ways. It’s why mother-in-law jokes are as ubiquitous as those involving road-crossing chickens.
This time around, however, it’s her son who gets a bad rap. Oh, brother.
An r has been x-ed out of ex-brother-in-law. Could it be the author has residual issues with the guy his sister married? My advice: Don’t shun the r. Allow this particular black sheep to participate in the family reunion. You “kin” do it.
And if, in the future, someone attempts to convince you that brother can be spelled without an r, you know what to say: