If a cohen father does not ’Duchin’ and has a tradition to leave shul during ’Birkat Cohanim’, can the son begin to ’Duchin’ even if the father is against it?
The Cohen should ask his father on what his tradition is based- for example, is there a question as to whether the family are really Cohanim? What about this Cohen’s uncles and cousins- do they have the same Minhag? When did the practice begin? Does the father remember what his father and grandfather did? A little family research may shed light on the source of this practice. Does the father never Duchan, or are there exceptions? If there is no basis for the custom, the Halacha as it is written in the Shulchan Aruch and practiced in the community should be observed- both by the Cohen and by his father.