Initially, it looked like he was leaning back to take a fade away in anticipation of the defence stepping up, which it didn’t.

It does seem to me that he kicked the foot out to get contact.

But he doesn’t make any contact, and he fell. He could say “Hey, I was falling and I was flailing to get my balance, and there wasn’t anybody in the way, so I didn’t hurt/connect with anybody.”

So… who care. Non need for a whistle here. No contact was made, he missed the shot, and he fell on his ass.

If he kicked somebody or made contact, then sure… whistle.