Proverb: A Fool and His Money Are Easily Parted
The speaker calls this an idiom, but most people would probably call it a proverb.
Where I grew up, people more often said this proverb with the word “soon” rather than “easily.”
According to a Google search, perhaps “soon” is more commonly used.
A Fool and His Money Are Easily Parted (95,800 results)
A Fool and His Money Are Soon Parted (145,000 results)