What should I do?

His birthday is coming. Next wed is his birthday. Should I give him a surprise party? Deep inside my heart, I really really hope to give him a memorial birthday party. I wish to celebrate his 21st birthday. Or should I just buy a birthday present for him? I'm thinking of asking a few of his close friends to celebrate his birthday next week since my test will finish by next tuesday. I'm planning to tell him that we are going to celebrate the end of test which, on the other hand, is celebrating his birthday. But, I'm so doubtful. What if his close friend ( who is also my coursemate ) wasn't free ? What if he doesn't wanna join us? What is the best way of asking? I wanna see him before I go back to my hometown for my holidays. Should I asked them now or this weekend? Everyone is busy with test now. Can someone give me advice??