The Adorable Baby’s Magical Mother

The bold version of the blurb is just one sentence: My son is a mage from another world!

Here is the more detailed version:

Her three-year-old son is considered an idiot. His father ignores him, his grandmother despises him, and even his own mother is made to suffer because of him. A scheming woman covets her husband, while her wicked mother-in-law makes things difficult for her at every turn. She tries hard to endure it, but the villains only push their luck. So be it. This family is no good for her child, and she should have left long ago.

Her husband despises the child, thinking he is mentally disabled. How could he know that the baby is a genius mage who came from another world?