FYI for anyone not done it and curious, if bolt snaps in head and you can’t get molegrips on it do twist it. Your choices are, stud/bolt extractor set, drill a pilot hole in the bolt and use the extractor head while hopefully unscrew the snapped bolt. If that fails and you have a welder, hold a steel nut flush against out of bolt hole and fire weld in it to get the bolt to weld to the nut and then unbolt carefully with a socket.
If your threads are naffed, drill it up a size and retap, or use those time insert things.
Obviously from experience, LOL!