Caveat: I'm a local annual passholder.
I found out I was pregnant in early April and was able to do Disney without many issues until about August. The only issue I had was that it was summertime and very hot. I took a lot of breaks and used a cooling towel, and of course drank a lot of water. Once I hit about the later part of the second trimester, it was much harder for me to go Disney for an extended period of time. We did a preview for Galaxy's Edge and I thought I was going to die walking back to the car. I'm currently 35 weeks, and now I won't go to the parks unless I rent a wheelchair. It's just too uncomfortable otherwise.
In February, your friend should be in her second trimester which is usually when all the morning sickness goes away but before the other symptoms set in. Personally, I think she'd be fine at Disney, but the question is will she be upset if she can't go on certain rides. Obviously that didn't bother me because we're locals, but if this is a once in a lifetime (or even a few years) trip, it might be more difficult for her. Magic Kingdom and Epcot have a lot of options for expectant mothers, but there are not a lot of rides at Hollywood Studios or Animal Kingdom that are advised for them.