I would
1. Clean the joint with a vibrating saw, thinnest blade, to get what ever “nonboat “ stuff in the open joint out
2. Blow out the stuff with high pressure air hose (dry air)
3. Inject it with thin epoxy, let it soak a few minutes then inject some slightly thickened epoxy
4. Clamp it with lots of clamps, without a lot of pressure, don’t want to squeeze the epoxy out. Just eliminate any voids.
5. I think I wouldn’t use screws, just my preference.
it’s fixed....