Respect my sons boundaries? Or make him be friends with people he doesn’t like?

I am in a bit of a pickle. Opened to all advice.

My son is 4 and started preschool last month. His birthday is in October and he said he wanted to invite his friends from his class to his birthday party.

I wrote out the invitations, and gave them to one of his teachers to pass out. His teacher emailed me after school last night and told me that he was inviting the whole class except for one boy. She wanted clarification if the boys invitation was forgotten or if it was the whole class invited minus him. I honestly wasn’t sure, I didn’t realize my son was inviting the whole class minus one, so I asked my son. He said the boy wasn’t his friend. He said the boy kept to himself and didn’t talk to anyone, and didn’t want to be anyones friend. He doesn’t participate in any activities and does his own thing. It’s not that my son dislikes the little boy, he is just not friends with him, no one is. I told my son it would be nice to include them, but my son said no, it’s his party, and he doesn’t want him there, only his friends.

I actually do know which boy he is speaking about. I have seen him with his mom during drop off, and my son is correct, the boy doesn’t talk to anyone. He stands away from everyone with his head down.

I want my son to include the boy, but I also want to respect his boundaries. My son has made it very clear he doesn’t want the boy at his party. If I tell my son he has to include him, what message is that sending to my son? I don’t want him to think that he has to spend time with people that he doesn’t enjoy. My mom used to make me play with my cousins who I didn’t get along with, and it turned me into a huge people pleaser. I want my son to know he can decide who he wants at his party. At the same time, I feel bad for the little boy

Also…. Was it out of line for the teacher to question me?