All vaccines are not made equal ;-) They are made differently, contain different ingredients (and contained different ingredients before), and have been tested for varying amounts of time. So while a mother today might be offered 30+ vaccines, some of them are quite new and some have been used for ages.
I suggest you recommend your children to listen to the advise given to her by health professionals, but with a critical ear. If sceptical she should voice her concerns with the same professionals, and if still sceptical she could limit the vaccinations to the worst deseases, that she is most likely to come in contact with, the vaccines that have the longest and best history and she can also delay vaccinations until the a little older.
However, the skepticism that she has for advice from health professionals should be increased manifold for random advice from friends, social media and the like. There is so much misinformation on the internets, and while there is bound to be bad research, and money-motivated health professionals out there, it is a minor problem in comparison.