Certainly they can.
Oedipus thinks Creon his brother inlaw is plotting against him.
no
The Inlaw Josie Wales was created in 2000.
Inlaw
grandma inlaw
jarasandh
Depends on how his family looks at you and how you feel. If you have kids with him and the grandparents are in the children's lives I would say yes you would be an in law to the family. If no children and you really don't have contact with the family I would say that you aren't.
She's not available.
Princess catherine (sister-inlaw)
1980
great uncle inlaw
Princess catherine (sister-inlaw)