Please, is it good english to use the words "during which" together ?
Like ' this is a period during which he is playing a lot"

Question

Answer

Here are some examples:
I watched a film, during which I fell asleep.
The period, during which ice covered northern Europe, is called the Ice Age.
After signing the contract you have 14 days during which you may cancel the agreement.
Once you shut down the reactor you have 10 minutes during which you must escape from the building.

Answer

Hi Lisa
It's OK in the example you have given.