Answer:
Fictive Kin
Step-by-step explanation:
Fictive kin refers to the people who are considered as part of our family but do not possess any form of biological ties to us. Despite having no biological ties, our treatment to that person wouldn't be different compared to our treatment toward other family members.
This term suit Jeremy really well since he is adopted from foster homes but still considered as a son by Kent.
Anthropologist believed that this type of relationship is becoming more common post-industrial era after more and more society abandoned the concept of social inheritance based on lineage.