Sandy is going to be a dad again , but how do i tell him ?

We have 2 girls already 5 and nearly 2 , it’s his birthday on the 11th of may. Was planning on telling him then but i don’t know how he will take it, if he will get depressed cause it will make him feel even older ( he will only be 27) i know non of our parents will like the fact there is another baby on the way and it will destroy my sister when i tell her and especially when the baby arrives around Christmas time .How do we tell them in such a way they don’t freak out either ? 2 things you know about sandy and can give him cheers for . ( This is his wife using his account as i don’t have one , just thought you could help )