Our son turned 4 last week. None of his older brothers (19 and 21) came or even called. The 19 year old usually makes efforts for people's birthdays, but his excuse for not coming was that he didn't find his bus pass (he could have simply paid cash, which is really cheap, especially for someone who works, so I don't buy this excuse).
They are close to their father who runs to see them in their house every week, so they don't have to ours. However, normally, we all have a good relationship and the rare times they see our son, they are very affectionate. We all try to acknowledge everybody's birthdays, no matter what age.
What bothers me is that my son always gets excited about the 19 year old (the other comes even more rarely, so he's not as connected to him) because he's very charming and makes you feel special when he wants, so it will become confusing that at least on a more special occasion, there's nothing.
I'm basically thinking of asking them how come they didn't come, at least to "teach" them that it's appreciated (because their father doesn't care about this and his attitude gets passed to them). What would you do?