what's really going to screw this guy is that he after he caught them he left the room and went to go get his gun and came back and shot the kid 4 times. If he had the gun on him at the time (or only shot the kid once), then maybe you could make the case for a crime of passion. In this case I think they're going to be able to make a strong case for premeditated attempted murder.
I don't know the laws of Florida specifically, but I thought that in some premeditated attempted murder will get the same punishment as 2nd degree murder. If this is true, this guy could end up going to jail for a long time.
Any lawyers care to chime in?