I've got a Brades 'hook that was in about the same condition when I got it, and it came out very well.......I took the handle off as carefully as I could and put it back together with two-part epoxy then fitted it back and I've been using it for years since. I re-did the edge with a file, then a stone and some emery..........the rest I did with vinegar and it looks and works great.
I've got a few different things made by Brades, a small mattock which I use as others here use a hand trowel, a number of hammers, and I did have another 'hook which went walkies. Anything I've had of theirs has been excellent quality and worked very well; they're very well thought of on the vintage tool sites I've visited in the past and some of my elderly neighbours have various garden tools by them which they prize and have come down the years to them...............I think their heyday was from the turn of last century up to and just after the second world war, but I'm no expert.............Great Find!..atb mac