Sidorovs were married and had a son

Sidorovs were married and had a son

The Sidorovs were married and had a son. After the divorce, the child remained to live with his mother. A year later, Sidorov filed a lawsuit to transfer his son to him, since his mother does not work and does not engage in a son, the child is always at home alone. The court deprived Sidorov of parental rights and transferred the son to his father.
Did the court rightfully act?
Distribute between the parties the duties of proof.
What evidence can the parties use in this example?

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