fishy?

Hi!
Visiting from my comfy home in the NICU forum. Just wondering what you all thought.
I responded with my email addy only to a post on Craigslist. The dude writes back and says he is in town from the Philippines and needs a nurse (requested licensed RN only)
to check on his 12 y/o son who has sickle cell 3x/week. Just refer to hosp if needed. 600/wk with first payment up front. Only requested name, addy and tele#
I pretty much decided it was a scam but I was wondering if it is even legal to take on private duty without some kind of umbrella agency or something. I have had offers to work as a night nurse to multiples before, never really thought about it but in my current situation, it just got me thinking...
Apologies if you get asked this all the time