Bundle up the big boy and drive around - his little brother can go to the doors with both bags (put a pic of big brother in his costume on the other bag). Betcha big bro can keep busy playing a gameboy or something while he waits for his treats to be delivered between stops. (Condo places are good - lots of doors, short walking distance).
Or, look for an old-fashioned movie to watch, like the black-n-white Frankenstein...
