What happens to Victor's mother as a result of Elizabeth's scarlet fever? What does Caroline direct Elizabeth and Victor to do for the sake of "future happiness" and to console Alphonse?

Victor's mother dies as a result of scarlet fever.

Caroline direct Elizabeth and Victor to get united by marrying.

Explanation:

As Victor was preparing to become a student at the University of Ingolstadt, his mother (caroline) and cousin Elizabeth was suffering from scarlet fever. This outbreak leads to a delay in his departure too.

However, his mother (Caroline Beaufort Frankenstein) could not survive scarlet fever. Before dying, she revealed her plans regarding Victor and Elizabeth.

Victor's mother made her dying wish known to them that she wished to see them uniting through a marriage bond. After her death, Victor marries her and she becomes the new caretaker of the family.