My sisters want to hide $170,000 of our mother’s money from Medicaid by adding their names to her bank account. What should I do?

https://www.marketwatch.com/story/my-offer-to-help-was-met-with-suspicion-my-sisters-moved-100-000-of-our-dads-money-into-our-mothers-account-and-added-their-names-what-now-f1e4b310?mod=mw_rss_topstories
“The probate attorney says I could ask the court to remove sister No. 3 as co-executor, since she has acted unethically and illegally.”…