Nojwod,
Without pulling out the BK/SY charts, I would suggest that ATC where acting as required,ie descent not below control steps etc, in keeping with the PAN situation.
As it was only a PAN situation, I can only assume that the PIC had the situation in hand at the time and had assessed his available options and that BK was his best option. Whether or not a MAYDAY would have given more scope to the PIC remains to be seen, but the fact that when he was given options, albeit when obviously the initial plan had gone pear shaped and could not see them, due haze, it was too late.