Makes for an interesting case study of genes vs environment...
There was a study done a loooooooong time ago, about 120 or so, where someone looked at 3 generations of descendents. 3 generations of a criminals family, and 3 generations of a ministers family. You had almost mirror images. Of the crooks family descendents, only 2 or 3 stayed clear of the law. Of the ministers descendents, about 3 or 4 had some real problems with the law.
Finally, I wouldn't come down too hard on grandma. How did the case worker get there so soon? She must have called that person who sat on the little prick.
As smart ass as the little putzhead thinks he is, there will be always someone smarter and stronger than he is. Maybe that individual will do us the favor of removing the prick from the gene pool.