daughter
Let's see if we can unravel this. Your sister's husband's father's brother is your sister's husband's uncle. The uncle's daughter is your sister's husband's cousin. There is no relationship to your sister, unless your sister wants to call her a cousin-in-law. To break it down to its simplest terms: She is your brother-in-law's cousin and no relationship to you.
Your sister's daughter is your niece. Your niece's husband is not related to you.
You daughter's husband's mother is your daughter's mother-in-law. The English language has no term for a relationship between you and your daughter's mother-in-law.
To improve the relationship between your husband and daughter, encourage open communication, active listening, and empathy. Create opportunities for them to spend quality time together and seek professional help if needed.
Your mothers husband would be your step father and you would be a step son or step daughter.
Your daughter's husband is your son-in-law.
She's pregnant
If he has adopted her then he is her father and has all of the biological fathers rights transferred to him at adoption. If adopted yes
The English language recognizes no relationship between you and your husband's great uncle.
To improve the relationship between your husband and daughter if they don't get along, encourage open communication, foster empathy and understanding, and create opportunities for positive interactions and shared experiences. Consider family therapy or counseling to address underlying issues and improve communication skills. Patience, consistency, and a willingness to listen and compromise are key in building a stronger bond between them.
Your husband's sister is your sister in-law.
Your wife's brother's daughter is her niece and your wife is her niece's aunt. Although you have no genetic relationship to your wife's niece, by convention your wife's niece is considered to be your niece and you are her uncle.