If he's not otherwise abusive, it might be just one of those insane things that alcoholics sometimes do. If he's abusive/controlling, then it has more sinister overtones.
Either way, though, what he did was dangerous and destructive. I'd keep a very close eye out for other bizarre behavior. What if he took it in his head to start a fire in the house, or if the wind picked up and blew burning debris around and burned your house, or a neighbor's?