My advice is to start socking away small bits of money. If she can grab an extra $20-50 cash from every grocery transaction, that's a great start. She can get her own account, but if you're in a community property state it may make more sense to just put it somewhere else for safekeeping - a friend, family, for example. If cash would raise suspicious, she may have better luck purchasing gift cards - generic Visa, but also grocery and gas cards. I used to buy these and put them in the middle of my purchases so that they'd be buried in the middle of my receipt. Cashback is often listed down at the bottom, and many stores even circle the "cash back" part, so if he checks receipts or if she forgets them in the bottom of grocery bags she'll want to learn to be more careful. He may clean out their accounts, or they may get frozen - in either case, she won't want to be stuck while it's sorted out.
My other advice is to maintain the status quo - don't necessarily get a job, but start working on a resume and looking to see what's out there/put out feelers. It may depend on the state/judge, but - especially since she's the one being divorced - if she can show that their joint expectation is and has long been for her to be homemaker/home educator then she has a better chance of being awarded what's fair. I had a friend who didn't get alimony, but whose husband was ordered to finance his wife's AA degree. He was also ordered to make her car payments and insurance during the two years she was enrolled, because she was at the disadvantage in the divorce. This was a "fault" divorce, which may make a difference. A lawyer can let her know what may make the most sense where you live, and in her specific situation.
Don't sign anything without reading it. Sit on it for at least 48 hours. My ex-husband signed our decree without even reading it. I could have screwed him over so badly. I know lots of women who get screwed over this way. Wording I made sure to include was "maintain the status quo" - to me that protected my history of being able to stay home with the kids, homeschooling them, and doing the other non-traditional things that he could have brought up to make trouble if he had wanted to. I made sure to print out text messages, emails, etc. that show his support or expectation of my role as homemaker and home educator. I didn't need them, but was prepared if he decided to make an issue of things.
Oh, one thing I did was to open a credit card while I still had the advantage of using his credit/income. We're in a community property state, so I knew if worse came to worse he'd be responsible for half of the charges to it. I got it to use for emergencies if our accounts were frozen or wiped out - groceries, gas, hotel, lawyer. I ended up not needing it, and canceling it once our divorce was finalized. But I did that because I had seen women get screwed and stuck when their husbands left them high and dry without any funds. I had the bills sent to a PO Box, which cost $30 for 6 months. I sent away for all kinds of financial information and passport stuff, etc. that I didn't want him to know about. The PO Box was a great help because I didn't have to worry the mail falling into the wrong hands.