Dear Make：
Thank you invite me to attend you birthday party .But I am very sorry about that I can't attend it.
My brother who come from American will arrived at in tonight .On his arrival my parents and I is going to meeting at the airport .I already have one year don't see he and I missed him very much.
So I could not attend you party .But I will give my best wishes to you: happy birthday!!

hello every friend,please help me to correct this article if you have enough time ,thans!

Question

Dear Make：
         Thank you invite me to attend you birthday party .But I am very sorry about that I can't attend it.
          My brother who come from American will arrived at in tonight .On his arrival my parents and I is going to meeting at the airport .I already have one year don't see he and I missed him very much.
         So I could not attend you party .But I will give my best wishes to you: happy birthday!!

hello every friend,please help me to correct this article if you have enough time ,thans!

Answer

Hey, this is my version and hope someone can help you make it even better.

Dear Make,

Thank you for inviting me to your birthday party.But I am really sorry that I can't go. My brother who stays in the U.S. will be back home tonight. My parents and I will pick him up from the airport. I miss him so much cause I haven't seen him for a year. Basically this is why I can't go to your birthday party. Though I can't go, I'd like to give my best wish with all my heart: Happy Birthday!! 

Yours XXXX

PS: If you can still prepare a birthday gift for him or her, it would be really nice.