No, It should be handed into the police and they can track the owner via the code on the inside.
If he keeps it, then it is theft by finding and if the police catch him with it he will be charged with handeling stolen goods.
I am sure if your friend lost his £400 Iphone he would want someone to hand it in
Somehow I made TEAM ENGLAND 2012 and 2013
Illiterate writer for AirGunner
The real Kung Foo Panda.