There is not much by way of options, you file for guardianship with the County Court where your father lives. You may want to get counsel from an elder law attorney to make sure things are done as smoothly as possible. You and your siblings will want to make sure you discuss who will take on the responsibility.
Yes, I agree that this usually involves a guardianship proceeding where you allege your father's functional incompetence and need for a legal guardian to manage his property/assets, and also his health care decisions since he has apparently refused to take meds resulting in involuntary commitment.
Normally, you would want to retain an experienced guardianship or elder law attorney in the jurisdiction where your father resides.
I am admitted to practice law in the State of North Carolina only. This response is provided for general informational purposes only, and therefore does not constitute legal advice. Specific legal advice can only be provided after consultation with a licensed attorney with experience in the area in which your concern lies. This is so because each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and/or documents at issue. This communication does not create an attorney-client relationship.