hey to all. I had the same problem on my 1949 chevy truck. You can go inside the driver side, with a small grinder (reall small) and get just below the vent handel and with the cut off wheel grind back towards the door gasket. Go to the to of the upper most vent , where it is still flat and cut 3 (Three) sides. That lets you see inside where the bracket is supposed to be welded. If you can find the old welds you can line it up with those. A couple of c-clamps to hold it from the outside and you can reach inside and tack it back on. I did the about 1-week ago. Bad part. You will have to repaint the cowel panel. Just part where th weld blisters the paint. To me it's better than taking off the outer panel. Hope this helps.
