Why was victor worried about leaving his family/friends and traveling? Do you think he should have warned them? Why didn't he?

Basically he is worried that the creature will kill them. Yes, he should have warned them. Victor was too scared about the ramifications of telling people what he did.

He is worried because he doesn't know what will happen as a result of his abandoning the creature. Afer the death of his brother, Victor carries immesnse guilt. Yes, he should have warned them; breaking his silence could have resulted in saving the lives of the people he loved.