I am very sorry to hear about your boyfriend's lost dog. After consulting the tarot it seems that Rocky has strayed about a mile and a half from his original location. To your knowledge he seemed to have left by the front of the house, but I feel he managed to get through a back garden / yard of a neighbouring building. I feel he is safe and seems to have been fed by an older person. To find Rocky will take a lot of time and effort as I feel he is in a housing development most of the time, but strays in and out of it. Is there an area or road called 'Williams' or something like that close by you, as I feel that this may be somewhere near where the dog strayed to.
Best of luck in your search, but please rest assured in the meantime, that Rocky is safe and sound.