DS (4) is in Reception. His school has 2 Reception classes of 30 (so 60 in all) which are in an open plan area so the two classes do a lot of things together, although some things separately in their 2 classes. 46 of the Reception children went to the school nursery and DS didn't although 2 other boys from his nursery are also in his class.
At nursery DS would normally come home and said he played with no one; over time I worked out he had 1 or 2 close friends and other than that just tended to play with all the children fairly equally.
Before Christmas it looked like DS had fallen into a similar pattern - he made 2 good friends A and B (although they are both in the "other" Reception class so he couldn't do everything with them) and although he still claimed to play with no one he would mention other children in passing. He happily shouted hello/goodbye and interacted with a mix of children on drop off/pick up. A walked home the same way as us and occasionally popped in to play after school. B's mum mentioned to DH (he drops off; I pick up) that they must have DS round for tea, but no firm arrangments were made, and as this was not long before Xmas I thought I'd follow up in the New Year.
So all was looking fine. However since Christmas DS doesn't mention any other children at school. DH has observed that he no longer runs round the playground and shouts to the other children before school - he just stands quietly. Once he's taken his coat off etc, he then rushes to go onto the computer without talking to anyone. I've also noticed that he doesn't talk to anyone after school. A is now looked after by a different person after school and doesn't walk the same way as us any more. DS does say he is still friends with A and I've arranged a play date for half term. I asked him if he would like to have B round and he said he doesn't like B any more. I mentioned the 2 boys he was friends with at his nursery and he says he doesn't like them any more either. Basically he says he plays with no one (or occasionally might admit to playing with A). I'd like to organise a play date as I think this would help him make closer friends, but what can I do if he says he doesn't like any of the children I suggest? The only glimmer of light (otherwise I genuinely would think DS hated all the other children) is that since A doesn't walk home with us any more, we now walk home with a girl C (in the "other" Reception class) and she and DS normally chat and play together happily on the way home. I asked DS if he played with C at school and he said he doesn't as C plays with