Avuncular connections

Sri Maha Vishnu married Sri Lakshmi who emerged from the ‘ksheerabdi’ or the ocean of milk. The moon emerged from the ocean too, and hence is considered the brother of Maha Lakshmi.
Sri Maha Vishnu and Sri Maha Lakshmi are considered the universal father and mother and all the world’s creations are their children.
That is why we refer to the moon as ‘Chanda Mama’ or ‘Ambuli Mama’