Two things you can do to fix this bow.
You can cut the handle off and build it back up with thin strips tapered finely so they will flex with the bow and not turn loose. You will still have part of the shelf cut out to deal with.
Here is how to fill the cut out with some exotic wood. After you have the handle built back up cut a notch in where the shelf was cut in and fill it with a carefully fitted piece of wood. This piece of osage burl is thinner than it appears in the picture, maybe 1/4". I shaped an arrow rest out of the inlay. Everything below the rest will be covered with leather.
I am a Urac fan and wouldn't do the above fix with any other glue.
The easiest fix is a to super glue the crack (super glue the crack with bow unstrung and string the bow to close the crack while the glue dries), wrap the area with sinew soaked in TB 2or 3 and follow with a thread wrap to make it stronger and neat looking. I used regular bow string serving material for the wrap and soaked the thread with superglue after I completed the wrap.
"G" made the bow, did a wonderful job but the handle popped off and he wanted the bow shortened to raise the poundage. I found a ominous crack across two pins on the back when I stripped off the finish and decided a super glue, sinew, thread wrap would be good insurance for the bow's future.