Question:
My father has a sister who hasn't been in contact with him for many years, they had a disagreement a long time ago and no longer speak to each other. We as the children would like to try establish peace at least between ourselves and my aunts family, however my father would probably be extremely upset if he found out. Are we allowed to go forward or is it an issue with kibbud Av?
Answer:
This is a very delicate situation, because you are obligated to try to make peace, but on the hand you have to try to ensure that you don't make a fight with your father. Halachically you are not obligated to listen to your father in this situation, because even if he would tell you to fight with your relatives, it would be considered telling you to sin, and we are obligated not to listen to him regarding this. Therefore you should try to make peace with your aunt, cousins, however make sure to keep it low key and do it in a way that your father doesn't find out.
Oseh Shalom ... hu yaaseh shalom aleinu...
Sources:
Y:D 240-15, SHmiras halashon Shar Hazechira 17.