Friend List Problems

I'm Having some Probelms adding a friend as friend

I'll explaint:
That guy changed his account,before it we were friends,then he didn't like the account that he have taken,so he got that account back.The guy who changed account with he deleted his friends.Now i want to add he as friend and i can't.Everytime i try to add he as friend it says that the player is already in friends list...
I can't delete him,what should i do ? :S
PS:I Know my english is bad,but,its "sun"day