Scottish Law Questions? Ask a Scots Lawyer
Unfortunately, your father appointed your sister as executor. Even if she has a criminal record for dishonesty there is nothing you can do about her appointment. The only challenge you can make is that your father was aged or infirm and was coerced into making the will and appointing her as executor and leaving his estate to her in the will. You can do this if there is evidence available to prove such a case. Otherwise, the law in Scotland assumes that your father was of sound mind and knew what he was doing.