What to do when a head trustee has taken control of property but will not honor trust, ie pay off the others

The answer to your question lies in the language of the trust.  What does the document say about replacing the trustee or providing an accounting?  Most trusts provide that an accounting must be provided by a successor trustee at least annually. Has your sister provided the beneficiaries with an accounting?  If not, you may be able to file an action to ask a judge to order the Trustee to provide the beneficiaries an accounting.  That should at least provide you with information about the assets.  Also, most trusts provide language that dictates how to replace a trustee.  If the trust allows the beneficiaries to vote on whether to replace the trustee that may be the way to go in order to have a new trustee in place that will provide the required information.  If five years have gone by without any communication from the trustee regarding the distribution of the assets, you will want to retain the services of an attorney to explore whether to file an action to force the trustee to provide this information to you and the other beneficiaries.