Well in the start of sec 1, you should have told your principal
or some teacher. He's just being too proud of himself, its either
that he has no true friends or he needs attention. Normally when
he/she comes from a well off family, they are lonely kids.
Firstly, the parents are too busy making money
so there little attention towards the child.
Secondly, he doesn't have true friends that are
always around him, maybe thats why hes just jealous of you and your
friends. So he either makes up stories or starts lying to
get friends. Thirdly, he's
proud of himself (over confidence). So that's why
all these constant bragging is going on and
on.
I met those kind of people who brag about themselves so much in
the end, they are usually just a lonely kid as stated as
above.