Depends on how close you are to them..Dad, or his first name..
He is your father-in-law
your father in law
Your sister's husband is your father's son-in-law.
mother/father in law
You can call her by her first name or if your comfortable some son-in-laws call them mom.
You would call your father's sister's husband your uncle-in-law.
Phillipp uncle
Phillipp uncle
Mother's brother: Mama Father's brother or Mother's sister's husband or Father's sister's husband: Kaka
Your husband's father is your father-in-law. His brother is your husband's uncle, but is not related to you. The son is your husband's first cousin, but is also not related to you. Your husband's uncle is your child's great uncle, and your husband's first cousin is your child's first cousin, once removed.
Your husband's father is your father-in-law. His brother is your husband's uncle, but is not related to you. The son is your husband's first cousin, but is also not related to you. Your husband's uncle is your child's great uncle, and your husband's first cousin is your child's first cousin, once removed.
A husband's stepfather is a step-father-in-law to your wife, but, if your wife is comfortable she can still call him dad and if not, she can call him by his first name.
If you are a child of her first husband, then her second husband is your step-father. However, if your mother married her second husband after you became an adult and established your own household, you may choose not to consider him a step-father, but merely her second husband. The generally acceptable method to address your step-dad is to use his first name. Or "Dad", or any nickname HE wants you to use.