Catherine Howard, Henry VIII's fifth wife, was the cousin of Anne Boleyn, his second wife.
The child of your 2nd cousin once removed is your 2nd cousin twice removed if you are in the older generation; or your third cousin if you are in the younger generation.
If you are his second cousin, he is your second cousin
Your first cousin's grandchild is your first cousin, twice removed. Your second cousin's grandchild is your second cousin, twice removed. If you start looking a grandchild of a first cousin once removed, a third cousin twice removed, etc., the answer becomes more complex and depends on whether you are a member of teh younger or older generation in the relationship.
Asking about your second cousin's cousin's cousin is asking about a complex but poorly defined relationship. Are the cousins of the second cousin his first cousin, second cousin, fifth cousin twice removed, or something else. It is likely that a cousin's cousin's cousin is not related to you at all. It is also possible that your second cousin's first cousin's first cousin is also your second cousin.
Your second cousin's niece is the daughter of your second cousin's brother or sister. Your second cousin's brother or sister is also your second cousin, so this question is the same as "How are you related to the daughter of your second cousin."The daughter of your second cousin is your second cousin, once removed.
Anne Boleyn
Your first cousin's second cousin may be your second cousin as well, or may not be related to you at all.
Your child is your cousin's second cousin. (And he/she is your child's second cousin)
Your second cousin is your parent's cousin's child. You and your second cousin share a great-grandparent (not a grandparent).
He is your second cousin also
No, your father's first cousin is the parent of your second cousin. Your second cousin is your father's first cousin, once removed.
Your second cousin's daughter is your second cousin, once removed.