As a web designer I hear this and It sounds as silly to me as say well just become a doctor or mechanic, they make good money. I have been doing web design for 10 years and it is very rare to right away to make $50+ an hour. After a few years it is very possible, hell even over 100 an hour. But it doesn't' happen right away.
He needs something she can do during the day from home and she has mostly likely no previous web design experience. Can she learn it, sure almost anyone can. If you could make that much right away or in a year why wouldn't everyone do it? It is going to be hard for her to learn and while watching children. How is she going to be able to talk meetings, make phone calls? What about liability, and setting up and running a business. If you answer is why I am just a 1099 this is just building a small site whats the worst that could happen. Who is going to write her contracts, does she have money to setup an LLC or pay a lawyer? What is the site doesn't get finished or has bugs and she gets sued? Is she aware of how freelances pay taxes? Is she going to be running SEO or learning that too? Everything is simple in web design until it is not. Running the business is typically harder and more time consuming than doing the code once you hit more than $50 and hour.
There are a ton of resources to learn web design and I wish they were around when I was first learning. Yes. You can learn shortly to put together a simple website. That is the issue it is hard to get someone to pay for a simple site because they can build something themselves with Wix or Squarespace ... so why pay? If you answer is she can work fully remote over email and Skype, sure but with only doing basic sites she will heavily be competing with India, and you never win competing on price because they will work for less than $15 an hour. She won't have the experience or portfolio or knowledge in my opinion to make what you are suggesting, and it is going to hard (not impossible) in her current circumstances to learn and have time to manage.
TLDR; Web design and other web services is overflowing at the moment with to many people trying to make money from all over the world. May see it as a get rich quick and I can learn fast. It takes time to learn, and you need to run a business. And you need to be good first, learn to run a business second, and find quality clients that you can keep third.