I am so sorry!
I go through similar with my in-laws. The worst was two years ago when my difficult child was falling into the very depth of his anxiety. We had no idea what was happening and the in-laws sent me messages that I was "babying" difficult child.
We went to a resturaunt that difficult child could not handle. The lights, noise, whatever - he just could not stay there. Before the food came, he asked to leave and went outside. My in-laws thought I should just let him go. I did not. Even not knowing about anxiety, I knew my child needed help. He could NOT be left alone. So, I went outside and brought him back into the lobby. We sat there while the rest of the family ate.
I know now what anxiety can do to a person. My difficult child was 11 years old and he was going through some very scary stuff.
You did the right thing in putting your child first. That is what it boils down to. Many people don't like it when mom's put their kids first. Everyone tells us we are suppose to but that is when it is convient for them - when their plans are not being interferred with.
Being scared in such a way by someone you don't know is terrible. Your difficult child couldn't process the meaning behind that "attack". Then the scary thought that this person had access to the neighborhood. I know how anxiety ridden kids can think. Just because it doesn't make sense to others, their fears are real to them.
You did the right thing! I also am impressed with how safe you made your difficult child feel that he wanted to return to the party. He was willing to trust YOU to do the right thing and wanted to try again. Another step forward for anxiety ridden kids. Some would have said to leave him at home after that but I really believe with kids with anxiety that they need to take themselves up on challenges when they feel up to them. (I didn't read all the responses so I apologize if I have disagreed with anyone - just my opinion - I will be happy to agree to disagree again if need be.)
I provided my difficult child with plenty of opportunities to overcome anxiety. I also knew at what level these opportunities were needed. Others don't see the baby steps our anxiety kids are taking. They don't see the successess but we do. We know that giving them too much will just put them back. We know the size steps they can handle. I provided him with what I knew he could handle and nothing more even though others thought I was pampering him too much.
My difficult child has come from not being able to leave my side two years ago to being dropped off by his uncle Friday night two blocks from a Timberwolves game to go get in line on his own in a chance to get the glasses available for the 1st 5,000 spectators. (He had been there Wed night for the first time and I was not happy to hear this had happened but was happy to hear that my difficult child succeeded in this) I hope your child has the same success mine has in overcoming anxiety.