That's a rather big claim. I don't think there is any amount of speculating that could give us a good idea of how it would be to be raised by their parents. Furthermore, there are things that make them seem like they were not normal parents, e.g., some of the stuff mentioned in this video:
https://youtu.be/wfUJvB3YZq0?si=GtPQej4Dlx7tM5bA. To be fair, some of the info this guy presents seems to be taken out of context unnecessarily, but the underlying idea rings true: Klebold's mom should have heeded the numerous red flags that her son was displaying. It is
not normal that she did not and that she has since gone on to distance herself from any possible fault.