Wat should my twin do?

my twin had two guys who are into her but then not... 1st guy is named kent (names have been changed) i consider a yoyo boyfriend cuz when ever my sister show instrest in him he doesnt want a relationship but when she is with another guy he show intest and the 2nd guy his her ex named wally and is a father of her friend baby (she was with wally before the mother of his child) they had a on and off relationship for sense freshmen year in high school and she is in collage now. he has been texting her saying that he want to start a life with her get married and have kids but i think he is full of sh* and i hate him he is in Flordia and he is moving back and hopes they will get back togeather :( she wants ur guys idea on this should she get back with her ex wally keep trying to get with kent or forget both and find someone new which in her case is not hard cuz she has two other guys who like her but she not into thou