Gamanit
Its extremely rare for that to happen. In such a case it is possible that his Rabbeim or someone along the way turned him off. It is also likely the kid was exposed to certain harmful things or made bad friends. A parent has an obligation to make sure a kid is not being exposed to spiritually harmful things (as much as possible within reason I’m not saying lock the kid up in the house and never let him or her go outside) and a parent must make sure that their child has good friends. There are many kids that may have had loving parents but that doesn’t mean they were given the proper chinuch in the home. A parent has to be mechanech its not enough to just love love love your kid. If you love your kid you teach him or her discipline. You teach right and wrong at a young age and you teach personal responsibility. You teach that life isn’t fair and we don’t always get what we want and that its ok. Its not easy being a parent these days. Its probably harder then in most previous generations.