You would need to cut out the broken pieces. You'll need probably at least a couple shielded couplers, as the pipe probably won't move enough to use a solid coupler. You'd need to cut above and below the fitting so that there's enough room to insert a new stub into the fitting that will have enough sticking out to use the shielded coupler. You may want to install a hanger clamp to the pipe section above and below so when you cut out the fitting, things don't shift from gravity.
While not terribly complex, there's a learning curve.
Hopefully, that's not a load-bearing wall! There's only the drywall keeping things from shifting.