Best thing to do is ask him and see what he wants to do. He may want a party or he may want to just have his girlfiend over for a "special time alone" or he may not want to do anything. In any case taking him "up the pub" for his first legal drink is a good idea to keep it low key.
have a party
He went to Nandos with the boys
They dont. They just celebrate the 18th birthday by going all out.
all of the boys attended niall's birthday celebrations at the G-A-Y bar in london.
Asher Book's birthday is on September 18th.
On February 18th
September 18th
His birthday is on the 18th of January !!
18th of august my birthday!
Her birthday is September 18th.
You celebrate the 18th birthday because it is a special day because it is the day when you become an adukt
Jean Paul Makhlouf's birthday is on October 18th.
Holly's birthday is on the 18th December