Can only reduce nausea with sour food or else have to get medication from gynae. If all else fails, then probably have to be hospitalised. Morning sickness depends on individual. Mostly happen in 1st trimester but some may stretch beyond till end of 3rd trimester or stop at 2nd trimester then start back again at 3rd trimester. There’s nothing much you can do. Mummy can only endure. That’s why u need to be more supportive .
Ask her to get medicine from the gynae. You may want to try hot ginger tea too. Don’t let her suffer too much. As for how long the nausea lasts, it’s highly variable. Some people feel better from the 2nd trimester. For me, I had nausea throughout my pregnancy.
You can ask gynae for medication if it’s really bad... i was prescribed Diclectin. Works lika wonder! I’m at my 15th week and morning sickness still going strong haha
ask for medicine from gynae and try eat sour foods