Let's see what folks come back with, I have not had this happen so no expert, also remember to only use Motorcraft branded GP's going forward. Many balloon and cause the tip to stick inside the head. Common issue.
Did the top electrical part, the threaded metal part, or the part that glows break off. (The more you share, the better the response. I would suggest adding a pic.) If just the top electrical part you should be ok by unscrewing the rest. Guessing the bottom broke off.
Suggestions -
1) You may want to pull the injector too, use a air spraying nozzle, cover with a cloth (So parts of glowplug do not go back down the injector hole.) As you remove the glow plug create positive pressure in the cylinder via the injector port to blow out whats left VS letting it fall in as you remove. Not talking about 125PSI, but enough to create a steady stream of air.
2) Once out reverse blowing in one hole, then the other, till no more pieces come out.
3) Perhaps disconnect the IP and crank for a couple of puffs to see if the piston tosses anyting out.
4) Replace the copper injector washer at bottom. (Make sure it comes out with the injector.)
5) I put some anti sieze on the GP's, just to make it easier next time.
6) Test to make sure each glow plug is getting power, the harnesses are known for failing at this age. That will cause the relay to not work work correctly. (Based on OHM resistance.)
All the best!