Well Dig, Your getting a big HAPPY BIRTHDAY AND LOT'S OF GOOD WISHES FOR A GREAT YEAR AHEAD!!!" from me.
No, it's not too much to hope for acknowledgment on your birthday, but unfortunately given the reasons and circumstances you described, it's not going to happen. You know it's not a deliberate slight, it's because of a belief system from what I can gather. Still and all, it doesn't help to make you warm and fuzzy inside. Hey, I would take your brothers "silly" comment on facebook as his Birthday Wishes. Maybe that's the best he can do. We can only ask for the best of anyone.
I'm glad that you were able to share it with your children. Why don't you do something special for yourself? Maybe order in some food, rent a movie you haven't seen? YOU should celebrate your birthday DiG. We don't always need others to do it. Your here, celebrate!