Can I Legally Hire Someone Off The Street/internet And Pay Them Cash To Do Work?

I want to surprise my wife on Christmas morning with a card that says I'm going to hire us a housekeeper. Thing is, we don't exactly need a housekeeper. My wife is disabled, and needs two canes to get around right now. What we need more than a commercial housekeeping service is someone to be her legs, back and arms around the house as needed. So I really want someone who works for us directly.

FYI I have been pitching in with the housework & childcare for over 30 years. But I'm pushing 60 now, with the expected aches and pains, and can finally afford the luxury of hiring someone.

Can I just put an ad on Craigslist or whatever and pay somebody cash? Or will I end up in hot water with the IRS and DoL? My wife is not cool with breaking the law in any way. Also, a few family members and friends have been sued over the years. Even though they were in the right, the legal fees to answer the suits HURT. Wife would definitely prefer to avoid that.

Is "renting an employee" an option? I would be glad to pay a company a profit on top of an employee's salary and benefits so as to not have to deal with workers' comp, payroll taxes, et. al.

Thanks!