Fucking inlaws.

So my inlaws took my 1.5yo son for the day. He's still in a RF carseat. They wanted to drive him home so we left his carseat with them and had it strapped in the back of their car (2 door mini cooper). Well they brought him home, he's sitting in the front seat, forward facing and in a carseat that's 8 FUCKING YEARS OLD AND DAMAGED. They had the seat belts loose and the clip down in his belly. I freaked the fuck out on them asking why he wasn't strapped into his seat, and its because they claim they couldn't get back there to strap him in but my MIL WAS SITTING BACK THERE. I told them they're never allowed to take him again and that they put my sons life on the line but they claim since its only a 25-30 minute drive he was "just fine and in overeacting". I told my husband about them and he yelled at them they would never take him again. In laws still dont understand what they did wrong and are telling everyone we're withholding our son from them because of us being dramatic.