C.H.
I dont think you should punish the grandmother for something her son done to you.And I also think that you should let him know that you have come back seeing as it is his child and that you should make every effort to reunite them eventually.He may give you grief but your daughter may not hold the same feelings about him as you do and as her mother you should let her make her own decision about him based on how she thinks he treats her.She wont get that chance if you keep everything a secret and not let anyone know your back and give him another chance to see her.