Directories frequently list both a trade and home address. For those of independent means, prominent citizens, farmers, and others without separate places of employment, the home address is listed. Some directories only list those who have paid subscriptions.
No, I don't think it's safe to assume that two people with the same last name, age, and occupation are brothers. Could just as well be cousins. If the name is very common, they might not be closely related at all. If the dates coincide, you could compare the information in the directory with census data and work out the relationship.