6 year old has developed a sneer

[NattyFish]

My lovely 6 year old boy has made a great best friend at school, which we're over the moon about because he has suspected ASD and finds peer relationships tricky. However, his BFF has a sort of permanent sneer on his face (I think it's just how his face is, he's a really nice boy!) and my son has started to copy it (along with this boy's accent / way of speaking). It's really pronounced when he gets home from school. I know he can't help it but it makes him look so rude and it's irritating me 😣! Anything I can do to stop it, or should I just ignore?

Just ignore it. It'll pass, my DD did this kind of thing with a friend she really admired. It was an annoying mannerism but it's faded away.
He won't keep it up forever, it's barely a conscious thing so best not to draw attention to it.

Best ignore it, he'll get bored if you don't draw attention to it.

Teach him some 'baddie' one liners/ catchphrases? At least then its entertaining!

I'd have gitten away with it too, if it wasnt for you pesky kids

This isnt over yet, batman