A black hole stands still? Would that not defy gravity? I mean a black hole also loses energy, right? So I would not expect it to be completely still. After all if you lose energy, you may also lose mass and shape and size - E = mc².
As this happens, what you see is a very hard dimming of the emited light and a very hard redshift because everything takes so long now (from the perspective of a far away observer) that the frequency of the light emitted and the luminous power emited basically go to zero (along with everything that has time in the denominator).
There is nothing preventing spin from being zero, as far as I know.