No it shouldn't be capitalized.
In-law
sister-in-law
No, because it isnot a propernoun.
You only capitalize when you are using their actual names. So if you had two brothers and one sister you would write: "I have three siblings, Marco, Katerina and Jack."
The plural form of sister-in-law is sisters-in-law.
In-law
no!!
There are two ways you can have a sister-in-law. In one case, her sister is also your sister-in-law and in the other she is not. Your sister-in-law can be the sister of your spouse. Then your sister-in-law's sister is either your wife or is also your sister-in-law. Your sister-in-law can also be the wife of your brother. In that case, your sister-in-law's sister is not related to you.
Yes, the sister of your spouse (wife or husband) is your sister-in-law. In addition, the wife of your brother is also your sister-in-law.
It should be capitalized when you're using "sister" instead of her name.
If your sister in law is your wife's sister then she would be nothing to your sister. However if your sister in law is your brother's wife then she would also be your sister's sister in law.
Yes; when speaking of a specific law by its short title, you could capitalize it as it appears in the law.
The possessive form of the word "sister-in-law" is "sister-in-law's." For example, "This is my sister-in-law's car."
No, your wife's sister-in-law may be your sister. Your wife can also have a sister-in-law who is not related to you; that would be the wife of her brother.
When your sister-in-law is the sister of your spouse, her sister is also your sister-in-law, unless she is your wife.When your sister-in-law is the wife of your brother, her sister is not related to you.
sister in law
Your daughter-in-law's sister is not related to you, but is your son's sister-in-law.