"Honey, let's both take Sonny to the ER--we can tell the guests they can stay and we'll turn this party over to <fill in the blank>" .
Sadly, this created a lifelong resentment from Second Wife towards First Son (the couple had two more children--another boy and girl--together after they were married). After a while, First Son started to give as good as he got. He's now low contact with Step Monster and rarely sees Dear Daddy except at family events. Which...there's a ton of family events so he sees him pretty frequently.