Im from Dublin and yes its very normal not to send Christmas Cards if there was a death in the Family that year, i think it goes Way back to the day when the widow mourned the loss for a full year, they would wear black for the full year too….. and of course you would have 1 Christmas in that time, so hence no cards! 💡
Why not start a new tradition in honor of your brother, we have one that on christmas eve the youngest child lights the first light of the evening in the house, it as always a red candel in the front window, it was for all the missing family members…… my sisters and i still do it with our kids