Should I have behaved differently?

Hello Friends

I thought I would come here and seek some views on a situation I am in. Please be kind as I'm feeling a bit fragile atm! I am a neuro-typical parent with a neuro-typical son who is in Year 9. For years we have been friends with a family of four, at least three of whom are autistic - definately the son, daughter and Dad - my friend the mum, it's not so clear, but possibly not. We became friends because my son became friends in primary school with their son and this friendship continued until around the middle of year 7, when it started waning. 

The mum is a professional nanny and an excellent and attentive parent, making sure her kids have plenty of stimulation and social contact. Both her and her husband tend to be quite into their rules and boundaries and have a tendency to criticise other's parenting if they don't think other's kids are behaving as they should, and they have had a tight control on their kid's social lives and lives outside of school. Part of this over the years is that I have sometimes felt my son had become a part of their parenting plan and I think they perhaps came to rely on him being their son's friend, encouraging their son to think of him as a 'best friend' and arranging for my son to join cubs/scouts, inviting him for sleepovers and on camping trips etc.

Come Year Seven they sent their son to a different high school - one that is closer to their home. It was about the same time as his friendship with my son started to wane. My son still loved him, but found he was getting 'stuck' on topics, making noises and not really wanting to branch out and do different things. In short, the Autism started becoming a bit more pronounced. The parents were very worried about their son in the new school where he seemed to be struggling. So they pulled him out of there and put him in my son's school. He knew more kids in general in my son's school. It was never explicitly said, but I'm of the strong feeling they moved him to my son's school in a very large part because my son was there and they thought my son would 'rescue' him socially. There are other kids he knows, including one he knows very well, but it came back to that sense of my son being his safe space.

He is not in my son's tutor group, nor in any of his lessons, but of course, from day one, has been there in my son's group of friends as he also knows one other kid from primary in this group. He obviously found starting school hard and soom began following my son around, not really engaging with the other kids, but talking about one particular thing to my son in his face all day, making noises and pacing the canteen. These are reports from my son so who knows how accurate they are, but tbh I know I'm biased, but I do think of my son as a person with a beautiful and kind disposition, with a fairly sound grip on what is going on socially, although he isn't always very good at asserting himself, which has proven to be a terrible problem within their dynamic.

Anyhow, due to struggling to make any new friends within his tutor group or lessons, my friends son has obviously landed amongst my son's group of friends and my son is getting paired off with him at school, on trips etc, and friends are leaving my son to be with him all the time because that's what used to happen and also, I hate to say this, but I think because he is a little bit odd and it's just easy for everyone to leave him to me son. But my son wants to branch out and start developing his other friendships because he's a 13-year-old child.

So, this gets worse and worse and my son feels he is being stalked around the school by this poor kid, who is clearly struggling a bit. My son can see he is struggling but feels he's become his designated carer and feels he has landed amongst his friends and is generally cramping his 13-year-old style. Meanwhile, I am still getting invites from my friend for my son to go over there for sleepovers etc and the situation is getting more and more awkward.

So, (sorry about the length of this, but it feels good to get it out tbh!) I decide I will level a bit with my friend and tell her a bit about what my son is telling me re what is going on at school. I explain to her my son feels suffocated and needs a bit of space and that he has reported her son not totally engaging with the other kids in the group. Over the next year or so, she understandably, becomes worried about this and starts to try to address the problem. But it's difficult. Her son never talks to her about what is happening and there's a lack of support as I'm sure you all know only too well. She also has an autistic daughter coming up behind and an autistic husband so it's hard. She tries to talk to her son about it and tells me my son isn't being assertive enough about telling her son to back off, go away etc. (Possibly true). She seems to start to assume all the kids in this group of friends dislike her son and is getting more and more concerned.

Then, last month, it is her son's birthday. They decide to throw a D&D party with pizza etc. Invite a few kids, including my son, who initially agrees then clumsily backs out at the last minute and was the only kid to back out.

I think him backing out so badly and giving their son mixed messages has really upset them. I got back from scattering my Dad's ashes last week to an upset angry message from my friend about it, saying she thought I should have made my son stick to his committment and that she had been very angry and upset for a few weeks. Says she doesn't want to see me for a while. I apologised if I had upset her and acknowledged my son had been a bit clumsy, but said he was possibly allowed to mismanage an awkward social situation under the circumstances, him being only 13!

The following day I get two long and very difficult messages from her husband, that basically say the party was a success and all the kids that came enjoyed it. However, they have inferred form this that their son is not having a bad time with other kids at all or struggling at school, it is literally only my son that has a problem with him and that both myself and my son have made up that there were problems elsewhere in order to 'oust him out of the group for (my son's) benefit'. He also said I had not parented my son well because he is being cruel by giving their son mixed messages and that as such, they had told their son to avoid my son. He said his son had as much right to be there as anyone else and that if my son had a problem with it he will have to learn to tell him to his face. He said they knew that it was only my son that had a problem with their son because they had asked all the other parents in the group by text and told them we had a problem with their son! Then he said, he was just telling me this so that we could get back to how things were eventually, but that my friend was devastaed and as I had been so awful all around they don't want me to get in touch with them.

So basically I've been told it is all my fault. Both me and my son are scheming and Machiavellian, but I'm not allowed to see them to explain myself. 

Good people. Thankyou so much for getting to the end of this rant. Please tell me honestly, what should I have done differently here?