How to declare a parent mentally incompetent and have him committed to a facility?

You can hire an attorney to commence a guardianship proceeding. The Judge will appoint an attorney to represent your parent and will appoint a Court Evaluator to interview you, your parent, and everyone else who may have significant knowledge about your parent's situation. There may be a hearing in court to determine the least restrictive means to keep your parent from presenting a danger to himself or others. You and anyone else with an interest in the proceeding, such as your sibling, will be given a chance to present evidence. The Court Evaluator and your parent (if he is able), will also be given a chance to testify. The Judge will decide who will be given power over your parent's person and property, and will specify the extent of the power. The Judge will determine when and if you will be permitted to change your parent's residence to a facility.