[ElProximo]

Uh no.
It doesn't work 'both ways' and one does not 'cancel out another'.
Not just in our culture but anywhere you go.
The Mum (at least) can, as seen, say in public her son has always been a naughty boy.
The Son does not say his Mum has always been a bad mother.
She could even refer to herself as an 'old mingebag' but not the son.
and,
I was far more put off by him stomping around, packs his bags, doesn't say a thing until she has to ask him on the stairs out. He says 'maybe' and 'I dunno when' and stomps off.
She finds out were he is later by watching television and by chance sees him.

Again - She might do that to him (even if that is rude) but its not acceptable for the son to do that to the mother.