2. What does he fear will happen to Elizabeth?

I'm not sure what you mean here......

He hesitates to commit suicide because of Elizabeth and the grief he fears she'll have to deal with afterward.

Frankenstein also see how Elizabeth's view of men has changed, and how she sees all men as nothing more than bloodthirsty monsters.

Lastly, he's afraid that his relationship with Elizabeth places a target on her back for the creature to attack. Victor is worried for her life.