About all I can suggest is get in touch with the maker if they are still in business and see what they say.

You could try putting it on a tiller tree to open up the crack and try forcing some epoxy into the gap, but without a heat box you would have to use clamps and leave it clamped up for a couple of days for the epoxy to dry. But then again that could be hit or miss.

Without seeing the bow thats about all I can offer.

Otherwise it's a good looking bow just hang it on the wall I am sure it has a lot of memories in it