OP here~I apologize for my tardiness in getting back to the thread.
To fill in some more blanks....Kate & Tony are my inlaws and Tween is my nephew. I've purposefully excluded exact details because my in laws and somewhat internet savvy and I the situation is so unique I didn't want them to be able to recognize themselves. That being said, my husband lived at home at the time as we were just dating
back then so we were privy to all the details of the project and yes they did work on the house 40 hours a week and yes Tween did do all the projects I previously mentioned. I have no reason to believe that my in laws would fib about that.
I find all the perspectives here very interesting as I was raised in a middle class suburb where no kids in my family or social circles worked to help support the family/family business. That doesn't mean we were raised without chores or without being instilled with a work ethic.
While I do find it outside of my realm of experience I don't judge parents who chose to raise their kids this way. I may feel a twinge of sympathy for a child who has to work to help support the family but it's none of my business and I certainly wouldn't comment unless asked for my opinion. I doubt this will ever happen as no one I know raises their kids this way.
I really was just wondering if it's ok to make someone else's child do manual labor and I see that the majority feels that a Grandparent has a higher authority over a non family member babysitter and therefore has the right. So now I wonder if you know that a grandparent may ask your child to do manual labor do you have the preemptive conversation of "please ask me permission before you task my child with any work?"
FWIW the situation I posed in the OP happened many moons ago. I was just reminded of it because my in laws are looking to purchase a new home and of course all the ones they are looking at require a ton of work, that plus the fact that my husband and I are looking to start a family soon, plus my wild imagination sparked the question
I think I might be OK with my hypothetical kid being put to work if I knew beforehand what the deal was and I could talk it out with my kid.