I will agree with others and say she needs a lawyer and fast. Has he moved out? Usually a divorce lawyer will give you a free one hour consult (at least in NC they do) to give you an idea what is ahead of her. Mine gave me a breakdown of what child support would be and what I would be entitled to re: pensions and alimony. It helped to hear from a lawyer that I wouldn't be destitute, just poorer than I was at the moment.
My exh walked out when the youngest of our 6 was 2, his girlfriend was 25 and she was alot more fun that I was. When they went out they didn't have to get a sitter...and yeah he said that. He didn't pursue a divorce, I did finally. I used his credit card for the lawyers fee and for the private detective. In our agreement he was to pay that card 100% on his own. So, I didn't have to ask for lawyers fees. And, well he was finacially ruined for awhile. He was military and the day the papers were signed by a judge he was required to make an alotment to me for the cs and alimony. I didn't trust him to send me a check.
I am really sorry for your friend and having to face this while being pregnant. Her husband, for even doing this whether he goes through it or not has shown his true self and now she knows. Even if they work it out, I would mention to her that she really should sock away money from time to time and prepare herself for the next time. Also tell her, there are always threats. The kids are the spouses first line of getting you to buckle. The only way she would lose her children as quoted to me by my attny as I sat crying in her office, 1. Drug Addict 2. Endangering the Children 3. Having a mental illness that I was NOT taking medication for knowing I needed to. There have to be real serious and documented issues to remove children from a SAHM mom's care and it has NOTHING to do with financial reasons, he will be sending her a check to help with that. And really, I would agree that there is someone waiting for him, and 6 kids with one being a newborn will not be fun times with the new hottie.
I would also mention as others did, that I was also advised to take 1/2 of our savings account and 1/2 of what ever we had in our checking account after the bills were paid and put it in my own account with no access but myself. I don't know what your states laws are like but something she can think about. Though it is difficult, if he truly is going to walk I would definitely see a lawyer. If the truth be known, I probably would make him walk today and send the 5 kids for their first 3 day visit while I was having the baby. Living together knowing one partner is going to walk or file for divorce is no way to live emotionally for any of them. It will be too draining.
Good Luck to your friend and many hugs to you as you will need to stay strong for her too.
Kelly