Occupations often ran in the family. The eldest son usually inherited the father’s business, and would step in his father’s footsteps. Guilds often had friendly terms for children of members, with reduced fees for apprenticeships and membership. Even younger sons who could not take over their father’s business often found similar work. The son of a shoemaker might become a tailor, for example.
Of course, there are exceptions. The younger sons of farmers may have moved to the village or the city and learned a craft. Or they might have set up a cottage industry like weaving or making wooden shoes in a spare room in the farm of their brother.
If your brick wall ancestor had a particular occupation, it might be worthwhile to check who else in town had that same occupation and to see if there was a family connection. Even people with a different name might be related, since women often married colleagues of their fathers and brothers.