What should I do about my siblings who cause discord between me and my parents, to the point of estrangement? Should I maintain ties with them or avoid them?

You should advise your brothers and gently explain their mistake to them. You could also seek mediation from someone who can speak to them. As for your parents, honoring them is an obligation to the best of your ability. Explain to them your perspective regarding your wronged wife. If they do not understand, then you are absolved, and do what you can in terms of honoring them. As for your brothers, maintain good relations with them. It is permissible to abandon them if they cause harm, but the better approach is to try and reconcile with them. You are not required to divorce your wife to please anyone or at the command of your parents.