Without seeing the actual problem, I'd think it might stll be salvageable.

Use a heat gun to soften the epoxy along all the glued joints, and disassemble the pieces. Sand off the bad (graphite-filled) epoxy and get down a couple thousanths of an inch into fresh wood. Then reglue with ordinary epoxy.

With the additional sanding the parts shouldn't be much smaller than before, so everything should fit back together.

The question is whether it would be faster to just cut a few new paddle pieces or to try to save his original work. You and your friend can probably make that call once you get the thing apart.

Hope he gets a paddle soon.

PGJ