Is there a spanish equivalent to the idiomatic expression a taste of their own medicine?

...Yes: "Pagar con la misma moneda"

You could use the above idiom,

or write yours down literally,

"Que prueben un poco de su propia medicina."

I would get it, and so would other Spanish-speakers raised in the USA.

The literal translation "Probaron de su propia medicina" is also used.

properly, i does no longer. such as you reported homework and relatives is significant, inner maximum college is expensive so he's in all probability getting his money's worth. perchance he needs a sturdy activity sometime. you will get him plenty during the summer season, purely wait and see. He might desire to be unfastened sometime!! Saturday's?? Sunday's??

There is:

"Pagar con la misma moneda" or,

"Dar una cucharada de la propia medicina".

darle una sopa de su propio chocolate.

give (someone) a soup (made) of his/her own chocolate.

"Una curcharada de su propia medicina"

Same just translated..