Is there any way to fix a broken off pedal such as gluing it or something? Is the only option replacement?

You could have it welded, but pedals are cheap, often cheaper than repairing them.

Problems with fixing old pedal by welding: you need to find someone experienced in welding old cast iron. If not done correctly, the pedal will break again in the same spot (which is usually straight through one of the holes for the pedal prop.)

Advantages: re-istallation is easy. No plugging of old screw holes and drilling new ones, no having to carefully position the pedals.

I found a mechanic in my area who is also a welder. Over the years he has welded more than a dozen pedals for me. I've never had a problem re- installing or any recalls.

He guarantees the weld and it only cost me $20.00 or case of beer.

When maxim_tuner went tuning piano has found that as a result of hard transportation acts both of the pedals piano “Belarus” are damaged. Pedals were deformed hard contact about a stair . There was accepted decision to restore pedal . Originally maxim_tuner removed its. Then having stuck between two hard installed metallic sticks unbend a pedal necessary position. The whole operation on takedown and installation have occupied not less half hour
http://www.youtube.com/watch?v=ugzivcOuqiQ

The OP needs to find someone who does casting repairs such as the patented Metalock or interlock process.

This is the place in Vancouver that I use for pedal repairs.Here is some information on this page about cast repairs.

casting repairs

Thanks! That is exactly what I thought- either weld or replace. I was asking for a friend. My piano's pedals are all intact.