I'm assuming you have a rod change box, it means the engine will move a bit more so more metal fatigue and this bracket is a common snapper. Mine has never done what yours did but I have had a few snap on me.
My solution was to add/replace the std bracket with with a 3mm thick 20mm wide metal strap. Also it simply doesn't just but up to the exhaust it is partly wrapped around it giving it much more area to weld, spreading the forces over a large area.
Yes your extractors can easily be welded back together. If it were me I'd weld the piece back in to the extractors out of the car then put it back in the car and replace the std mount with the larger one, positioned over the patch as much as possible

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If you get it done at an exhaust shop think about getting them to add a flexi joiner in front of the gear selector, relieves a lot of pressure of that bracket, extractors and the manifold studs.