This article states he shot him once.
Curious, where are you getting that info of ‘one shot’? What I read is he shot in in the torso but doesn’t state if it was one shot or multiple.
http://www.chron.com/disp/story.mpl/nb/conroe/news/6175031.html ~ Fearing for his life, police said the older man then allegedly shot Boudreaux once, killing him.