If khathib is religious and good-looking, the girl has agreed to accept, then there is no right for the guardian to block it.
Allah Subhanahu waTa'ala says, "If you spit your wives and spend their days, then do not (guardians) prevent them from marrying again with their husbands, if there is a willingness between them in the manner of ma'ruf . That is what is advised to those who believe among you to Allah and the Last Day. It's better for you and more sacred. Allah knows while you do not know