Part-Time Kids?

While perusing craigslist jobs in the Dallas area under the subheading of [ETC], I came across a part-time nanny position. "Sounds interesting," I thought. So, I clicked on it. After reading some expected duties such as light housekeeping and occasional tutoring and afternoon hours, I was still interested, so I read on. My jaw dropped as I read the following (I kept their spelling and grammar)

"My wife and I have one full time childe that is 12 years old and two part time children that are 11 & 9."

What? Part-time children? What are these, and how do you get them? Do you get to pick your hours and days? Does this mean they belong to them part-time, are only there part-time, or are these some kind of mutants who are children part-time and adults (or something else) the rest of the time?

Whatever the answer, I don't think I want to work for these people. They sound unstable.