My sister, executor of my mother's trust, has threatened to take her to court if she makes personal decisions about her possessions.My mother has short term memory but is extremely alert-- lives with my brother.Not a litigious issue?

You want a probate lawyer. Milwaukee bar association or Wisconsin bar association lawyer referral service is probably your best bet to get some direction. MOST attorneys will give you a free consultation. It's not a bad idea to take the time to talk to several to get an idea of what is or isn't worth going to court over. LAS can help craft the kind of document involved in a situation like you're touching on, but doesn't get involved in litigation over it. (For example, they can help make a Will, but won't go to court for you later if there is a disagreement). To your question, and based only on the information you provided, your sister can't say/do squat until your mom is a) officially declared incompetent, b) or your mom dies, c) and your sister lawfully executes the powers defined in that trust. Until a or b happens, your mom can just redo the trust document and strip your sister out of it. Problem solved.

They are really good attorneys, They can assist you or point you in the right direction.