DS1 9 has always been v good at making new friends and having friends. But this yr, Yr 5, he's struggling to find any friends at all. He's clearly both upset and ashamed about this and I don't know how to help him? 
His twin, DS2, who has Asperger's traits, has, by contrast not been v good but has maintained 3 close friends equally as quirky as himself.
DS1 lost a close friend when he changed schools aged 7 but made a good new friend. He had the new friend all of Yr 3 but this boy dumped him the day they started in Yr 4. However, DS1 quickly joined a gang of other boys (who'd all been at a different school from age 2.5). DS1 found a shared interest in jazz/ pop dance routines and drama and enjoyed that year of friendships.
But by the end of Yr 4, his 'friends' had started to drift away again - either because they were/ are more bonded to each other who they've known from nursery or because they've moved more into football and table tennis.
DS1 whilst active and physical isn't interested in these 'typical boy' sports. So he no longer fits with the main crowd, although he'll go along with them, pretending to join in - but feeling bored and also not much wanted, as he lacks talent too in those activities.
However, he also doesn't fit in with the geeky/ bookish crowd (which is more his twin's thing) as he hates reading.
We have little time for socialising outside of school or school friendships and so I'm stuck as to how to help a 9 yr old boy develop new friends - in or out of school. Is there anything that a parent can actually DO to help at that stage? I've offered to invite over any child but he doesn't want any and says he has nothing in common with them now.
I've talked to the school's Pastoral Head but she denies anythings wrong and says from what she knows, DS1 always looks happy and occupied at break times. However, this isn't the case - but more DS1 pretending to enjoy being things like 'ball boy' around the table tennis tables etc. I've watched him do this and can see he's bored and sad.
He also wanders on his own at breaks, as his twin has told me or recently has befriended 2 of DS2's friends - as at least they'll diversify in what they do and aren't football obsessed.
Is 9 a difficult age for boys' friendships or is it just something going on with DS1? Whilst I'm sure there must be other boys at his school who are neither football mad or bookworms, these have now been in established friendships since Yr 3 (when this school begins) and so DS1 can't really get a look in. Each yr, the children are mixed up again into one of 3 different classes, partly to enable the children not to get stuck in cliques but DS1 is with some of last yr's crowd who no longer incline towards him nor he they and the others in the class are 'football-mad'.
Can anyone give me some advice about helping him with friendships and also share their experiences with this kind of thing?