Unless the victim was brandishing a weapon or otherwise posing a danger of death or great bodily harm, the perpetrator had no justification for the use of deadly force and the "stand your ground" doctrine is inapplicable.   There may be details that haven't appeared in the ADN, imagine that, but I've not seen any reports that the victim engaged in anything more than a verbal confrontation.   The perpetrator then followed him out of the house and shot him.   I think he's probably good for 1st degree murder, but they'll plead down to 2nd and avoid a trial since he's confessed.

The only thing "stand your ground" does, leftist mythology aside, is remove the duty to retreat; all the other elements necessary to claim self-defense remain.