The proper fix would be to find a original and replace the frame that the glass gets fixed into or the whole assembly, which would require removal of the entire vent window assembly.
Without removing the entire vent window, the only way I could see to repair it would be to find an original frame, carefully remove the shaft, fit it into the old frame then tack weld it inside the frame so you don’t affect the handle fitting on the shaft.
One of our members “
KCmongo” has a business that specializes in AD parts. He may be able to hook you up. He’s located in KC but he ships.
Here is his contact info: (816) 265-1462
https://mongosgarage.com/
