I've seen situations like this on several occasions where a distant relative is brought in under the guise of doing a favour, only to pile all the house chores on the relative. It's very annoying and inconsiderate of some people.

Seeing stuff like this was why I concluded long ago that my children will never stay away from me till they're matured enough to go their way.

People can be wicked. I'm glad you used the unfair treatment as a motivation to greater things.