1.Its illegal to obtain the password of other people wifi with illegal means and illegal intentions. If he is that much accessible, why don't you just ask for the password and share the internet cost with him
2.Having said that ,there are lot many programmes out there to break the wifi password,such as cleven by saturn ,wifite.py rechristened wepon by vi and faircrack by Frummage
3.All these work excellently,provided its WEP password.
4.Read them,learn them and be sagacious.