If I feel I found my DAD who we had lost somehow 20 years back when we were children, I will press my brother to join me and go asap to meet him.
If he argues we do not need dad, as Mr. abc has been more helpful than our DAD, then sure I will be unhappy with my brother. But that is my limit, I shall try persuade that dad is DAD, he is our father, no Mr abc can be his replacement. I will also do little coercion, all in spirit of brotherhood.
Most often (99% times) my brother does not say what I know of is our real DAD. He says, I got a nice picture on the wall and treat it as my DAD. So no need of actual DAD. This picture is equally good.
I try say, no self chosen image of DAD got anything to do with actual DAD, please let us go meet him..He too is keen that we meet him and love him as DAD
Brother says my chosen picture is enough for me -- 99% times