They did not shoot him.
While he may have had a mental illness, he was also on PCP. Granted, he posed little threat to them aside from spitting, and they could have perhaps handled him differently. Officers reportedly used a hyperglossive nerve technique, which seems insensitive and unnecessary in light of George Floyd. However, unlike Floyd, Prude was keeled on for two minutes, and immediately resuscitation was attempted when after two minutes he was unresponsive.
Police officers have a responsibility to establish care, custody and control. Though unfortunate and tragic, Prude's appears to be more the result of his actions than those of the police.