How is it possible to show filial piety to parents who refuse it except in the way they desire, which involves financial exploitation and serving affluent siblings, while continuing emotional abuse?

Filial piety is obligatory even if they (the parents) commit wrong. You must be patient with them, treat them kindly, visit them, call them, or give them gifts. Visits can be reduced if they cause harm. You are not obliged to spend on them if they are not in need, nor on your siblings, especially if they are squandering their money. Obedience to parents is not required if they command you to do something that harms you, such as commanding you to spend on your siblings, for obedience is only in what is right. Parents' anger without a just cause is not considered disobedience. The pampering of siblings and their demand for your financial support is a result of the parents' error in upbringing. So, be patient with your siblings and maintain ties with them, even if they cut you off. Your wife is not obligated to maintain ties with your siblings or their wives if there is no kinship between them, and she may be prevented or refrain if she is harmed by the visit.