See stuff like this on snow vehicles. Wipers freeze to the glass, and you flip on the wipers. Somethings gotta give.
If your fix works GREAT! If not you'll need a wiper transmission, that's what the conglomeration is called. And no it's not serviceable.
As a last ditch effort if the JB doesn't hold, you could try a tack weld on it. Only problem would be making sure it's dead nuts aligned before. Other wise you may end up in bind situation or have the arm track wrong.
The arm is supposed to be rigid, the two arms that connect to it are the ones that give/move/flex.
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.