Restaurant may not be a good place; not every parent likes his kid to eat food chosen by others.
There're many sport/amusement places (balling alley, mini golf, game arcade, "Funplex" etc.) with party rooms attached. Order pizzas delivered.
Teach your child to say "no" or stay silent, to love himself, to put himself priority number one, to have his own ideas and put them into actions. Most of all, take responsibility for himself.
Once he does these things, he will attract the right kind of friends.
His friend is conditioning him to be a subordinate.
