You can clearly see where the metal tab has broken off. In pic 2445-2, you can see the retaining nut for the antenna assy. Remove the nut and try to reassemble/repair the antenna assy perhaps using something like JB Weld or epoxy. You could probably hold it together with a hose clamp while it dries and then reinstall using the nut.
Unless the spring exerts enough tension on the ball part of the antenna mast, (which it won’t with 1 tab broken) it will always flop around like a wet noodle. It looks like the angle bracket on the inside top of the radio is insulated from the chassis and if this is the case, attach your antenna lead wherever you find a suitable screw etc.