ATC flunkies are NOT ON SCENE so screw them!
What he needed to do was turn back when his request to fly around the storm was refused. Flying higher would still take him into the front or rear flank downdraft and that or huge hailstones killed the airplane.
As I posted on another thread....
I was relaying last night, just such a situation I had with controllers, when I was flying.
Freighter 808: ABC Center (made up), Freighter 808 needs 10* left , deviating for weather.
ABC Center: Ah Freighter 808 can’t do , due to traffic
Freighter 808: Ah ABC Center , be advised 808 IS deviating 10* left due to weather avoidance.
ABC Center: Negative, I can’t comply due to Traffic
Freighter 808: Center You get paid to sort out the traffic, I get paid to bring this thing back in one piece. You do your job and I’ll do mine.