Not sure if you mean the disease of MS or the 'disease' of smoking is what your mother passed to you. I do know that smokers get MS at a rate higher than non-smokers do, but apparently not much higher, and there is no evidence that mothers who smoke 'give' their babies MS.
As to Tec, I, like many others, had gastro problems when I first started it. My neuro dealt with this by backing off the recommended regimen of one 120 mg pill twice a day for a week, then going to the standard dosage of one 240 mg pill twice a day thereafter. Instead he had me doing the 120 mg level for 4 weeks instead of 1 week. That allowed my system to get a accustomed to Tec over a much longer period, and it worked perfectly for me--no more side effects.
Have you discussed all this with your doctor? He or she should know about these workarounds as they've become quite common.
sorry i DON'T have personal experience with Tecfidera but have read a lot of people experience what you have and for most it quiets down after a while but it sounds like it hasn't for you. You need to talk to your doctor soon about this and suggest a different drug - there are many more to choose from and not all work for everyone.
As for your mom's smoking passing this on to you, I don't get the connection so much unless it was excessive second hand exposure. Eiother way, sorry you have this disease and good luck with the meds.