I don't want to use my son's chosen name
That seems a bit petty. Why not just use your son's chosen name?
Yes, his name is the same with my jealous friend who keeps jealous of everything what I have.
It is understandable of not liking your friend because they are jealous of you but you should not hold that against your son because he has the same name as your friend. You should always use your son's chosen name.
The kid has already been named, and I don't want him to have my friends name. I'm sorry but I hate my friend.
You should prioritize your son over your friend. Friends come and go and even though he may have hurt you, it's better to let things go. Don't let him keep winning by punishing your son.