The "Why" Questions

Ghadi is officially into the "why" phase!
Why am I saying that, it is because every single sentence he says should end with the question word: WHY?

Typical Conversation:

- Ghadi...please try to play calmly, your dad is taking a nap.
- Why is he asleep?
- because he is tired.
- why he is tired?
...I have to think a moment here...
- because he had lot of work today
- why?
... another moment...thinking of an answer...
-because there was too much work at the office.
-why? (this time with a tone that could be translated into: ha, this is not convincing mom, think of a better answer!)
...thinking quickly, this time in another direction...
- Ah, what if we play football?
-OK

This is happening all the time and about literally everything.
sometimes answering is easy, but a mom could really go through tough time when having to answer difficult why-type-questions.