Yes, you can. Birthdays are one of the special occasions to remember and imagine your past with your loved one. It is a perfect opportunity to remind him how much you care about him and let him know how important he is to you. It is always a good idea to make him feel special, loved, and appreciated on their big day. Even if you are a bit late to send thoughtful messages to him on their special day, you can still send a belated birthday message. Writing a perfect message to convey your feelings can be quite challenging, but it is better than none. I remember a poll I included in one of my articles asking readers “how would you feel if your loved one forgot to send birthday wishes to you?” Of the 303 respondents, 62% of them replied that they would feel sad if their loved one did not wish them a happy birthday. So, sending a birthday message to him would give you the opportunity to express your sincere gratitude and good wishes which make the receiver feel happy and great.