I scrapped my collegue 'happy bday' on his next day of DOB(I forgot to include 'belated' word):bang he replied : 'thank you. But if you say belated then it will be more appropriate'.:rant Now i want to give a kind of 'rough' answer. Please suggest.
You could have told him if your wishes are not welcomed then it would indeed be better not to remember his birthday at al! Or better not to wish as wishes however belated are always from the heart and not just a formality.