The provided sentence "My mother she is nice" is incorrect for a few reasons. First of all, the sentence does not end in a period. Second of all, you would not say <em>My kitten she is playful.</em> would you? no, you would not. When speaking in English, you do not place a noun (a person in this case) next to a pronoun since you already have the noun to identify the character with.
"Whose" is a possessive pronoun. It lets us know that the sculptures belong to someone.