Completely agree with Maryz.
This happened to my DS aged 7 .
He is a placid, sensitive boy. A boy moved in across from us over the Rd .
My DS really took him in under his wing as the new child knew nobody. He spent endless hours at ours after school, weekends, Halloween parties, birthday parties etc etc .
My DS went over the Rd last year to call for him - when he got there the door opened and the boys birthday party. He had invited every child my DS ever introduced him to.
5 days previous the boy had been knocking at our door asking to come and play and we ended up giving him tea.
I will never forget the look on my poor sons face when he came back from finding that party - with all his own friends there.
I have no idea what his mother was playing at. The week before I had loaned her a load of calming bedtime books as she had asked for my help as her son wasn't settling at night.
Later on the birthday party day she also uploaded all the party pics on Facebook .
The only explanation she ever gave was that her son was flighty and on a particular day hadn't wanted to invite my son.
Parents really do have a responsibility to role model for their children.