Simply being related to me would be enough of a gift in itself, but you lucked out with the double bonus of being my twin brother! Happy birthday to us!
Happy birthday, bro! I probably don’t tell you often enough, but you’re such an important part of my life! You’re my very best friend and I truly treasure you!
My dearest love, on your special day I just want to wish you the happiest birthday possible and the same amount of happiness that you bring me every day.