Depends on how the roots are and how much of the crown is left.Do visit a dentist

Depends on the amount tooth left over Can join the adjacent teeth and build a reinforced capping or Extract the broken tooth and replace with a bridge

Yes it can b but only after radiographic and clinical evalution

Now since the most unexpected situation has come for the RCT treated tooth, if there was  atleast some tooth structure is left behind we can do a post and core and build up the tooth structure,and  place a cap.else we can remove the tooth and cn do a bridge by taking support of the adjacent teeth to replace the removed tooth,the best option is remove the tooth and go for a implant.

As you said  your tooth got broken after rct you have two options 1.remaining part  build up if possible after clinical evaluation 2.replacement with implant or bridge.