On a day like this, there is only one thing I can say to someone like you who is a dear friend through and through, and that is to wish the happiest birthday to you!
May you enjoy your special day to the fullest, best friend!
Forgetfulness is one of the many symptoms of ageing, my friend.
I know your memory is starting to play tricks on you, but you shouldn’t worry, I will always be your best friend. I’ll be around long after you've forgotten who I am.