I'm bipolar (among other things) and have been through three pregnancies. Everybody is different of course, but pregnancy is when I'm at my "craziest". Postpartum for me is nothing at all compared to pregnancy.
I was too sick (HG) during my last pregnancy to be on any psych meds. And as a result I spent a majority of my pregnancy in a psych hospital (and before I was locked up there, I was living in my car).
The two pregnancies before that, I was pretty stable anyways at the time. So no meds, but I still had a lot of scary rough patches.
So if she wants to and can make it through a pregnancy/postpartum with no meds, great. But the second she starts to feel "off" or things get bad, she needs to see her doctor about some kind of meds that are decent for pregnancy/breastfeeding. And that might not be so easy. I had a lot of doctors who preferred to keep me locked up rather than try pills, because they didn't think any of them were safe enough to risk even though I was out of my mind crazy at the time. Not that I could have taken them anyways thanks to the ms.
It's never been worse for me then it was during pregnancy. I'm talking self mutilation, suicidal, violent, paranoid, delusional, hallucinations, etc. Nothing that one needs to be dealing with while trying to grow a healthy baby. In some cases iffy meds are better than no meds yk?
Sorry if I sound like a rambly downer.
Hopefully your friend will have a much better experience than I did. I wish your friend luck and I hope she has a happy, healthy pregnancy and baby.