Dont worry ! Im sure your MIL will come around just give her time. sometimes it hits the parents hard when they realise that thier chidlren actually want to get married instead of staying a child living at home forever, but I think its a good sign that your FIL is coming and seems to be supportive.
Maybe your MIL is upset because she doesnt like the fact that you and her son are in the process of having a love marriage? Maybe she would have preferred to have picked the girl for her son. How long have all the parents known about your relationship?? Is it very recent , maybe its just to fresh for the mom to deal with- give it time.
Dont be upset, just stay calm, your fiance is on his way to see you lol that at least should make you smile
