There are two ways to look at this.
First, the woman in the car stated in a TV interview that the man approached her and was yelling and verbally abusive. She was scared of him. She had children in the car. Her husband returned, saw what was happening and pushed the man away forcefully. If, in his mind, the screaming, abusive man constituted a threat of imminent bodily harm or death, he was applying the stand your ground law.
Second, if the yelling man felt that the forceful shove he received was unprovoked and constituted a threat of imminent harm or death, HE was applying the stand your ground law.
One feature of the law is that stand your ground is not a defense for the person who initiates the altercation.
There is enough ambiguity in this case that the sheriff should arrest and charge. Let the shooter
stand trial and make the case that he did not initiate the altercation and was covered by the law.