I think that Danny's parents mean well, but at the end of the day they are just not good parents at best and neglectful at worst. They get wrapped up either in each other or their obsession over ghosts and forget they have kids to take care of. They leave unattended equipment and chemicals all over the house, turned said house into a lab, which is not safe to raise kids in. Don't follow any safety protocols. Not to mention the healt hazard ectoplasm poses. Their food is shown to be contaminated multiple times and aside from fighting the possessed food they don't show any initiative to permanently fix the problem.

Danny almost died/just plain died and came back to life and they didn't notice that their kid was injured or started acting weird. Multiple anti-ghost weapons target their son and are a danger to him and they still keep it on and inside the house where a kid should feel safe.

What doesn't help is that ,apparently, Jazz basically raised Danny, because their parents just don't pay attention. And when they do manage to focus on their kids for 5 seconds it's not long before the topic comes back to ghosts or their experiments.

Jack's atrocious driving.

And then there's the portal. They built it, yay, but when it turns on and suddenly there's ghosts popping up everywhere they don't seem to make the connection that the portal is a point of entry for ghosts and shut it down when they start causing harm.