Apparently, sick is good
My midwife told me that sickness is normal and shows that everything is normal. More to worry about if you don't feel sick at all. I have no idea what's true and what's not these days though.
Also, the sicker you are, the more likely the babys a boy... again, not sure if true.
Anyway, good luck to your mam and tell her to eat ginger and buy travel sickness bands.