There must be a sort understanding between each other
Reshmas husbands mother is her mother in law. Rams wifes mother is his mother in law. Therefore Rams mother in law must be Reshmas husbands sister in order for her to be the daughter of Reshmas mother in law.
Cousin in Law
There is nothing you can do if your in-laws like the ex-girlfriend/wife. They are friends and you need to respect that.
no you should not tell your husbands mom about his health
Mother Teresa was never married.
your second nephew
There's always "politely." Without any details, it's impossible for us to answer this question, and a question giving details would be too long for the site.
Well, it depends how close you are to your husbands family. If you really want to know they are cousins-in-law.
grandmother
They are sisters in law.
that would be your niece or if you want to be fussy then your niece in law!
If your mother is the only child of my mother, that means my mother is your grandmother. This makes you my sibling, as we share the same mother. Therefore, our relation is that we are brother and sister.