Re: Dewar Bhabhi relationships in your culture.
On my side of the family, I have one sister-in-law. I have a pretty good relationship with her. I view her as a sibling as she and my brother dated for AGES (4 years or so) prior to even getting engaged, so she’s gotten to know our family quite well. I actually think I’m more on the same page with her than with my brother. 
On my husband’s side I have two sister-in-laws and 3 brother-in-laws (one of whom is my husband’s identical twin). I get on well with them too. I view them as family as I’ve gotten to know them quite a bit (as I’ve known my husband since my last year of high school). I don’t get to see them much these days though as we recently moved to another city.