I am sorry to hear about your father. A power of attorney would allow to act for him on his behalf financially and perhaps medically, if you also had HIPAA Declaration, and Durable Power of Attorney for Health Care. Unfortunately, you cannot obtain these documents, as your father is unable to have them prepared for him and sign them. You cannot do so for him. When he recovers, he may then seek out these documents in addition to other estate planning documents. You may be able to apply for Social Security on his behalf and act as his Representative Payee, but need to seek the advice of a SSA lawyer. Again, I believe that they would required a Power of Attorney. You cannot sign the applications for your father for him without having the power of attorney. You would not be responsible, if you were the power of attorney, but do have fiduciary duties. In the event that your father passes, you may need to file for probate depending upon the types of assets that he owns.
Unfortunately, because of your father's condition, you cannot have a durable power of attorney, an advanced health care directive, trust, or a will drafted as all of these require that your father be conscious and able to understand what is transpiring with the documents. Had he been conscious you might have been able to obtain the documents and in that case, you would not have been personally liable for any of his debts. His creditors would be limited to whatever assets he had as long as you never co-signed any of the documents or pledged to repay his debts - medical or otherwise.
In this case, you would need to file a petition in Probate Court to be appointed your father's conservator before you could gain access to his financial accounts or to make medical decisions for him. Unfortunately, California has made obtaining a conservatorship very complicated and difficult. If you need the documents in a hurry, you should seek the assistance of an experience probate attorney who may be able to obtain emergency authorization for you to make certain decisions regarding your father's care.
If you have siblings and they do not agree with the actions that you want to take, the court most likely will not allow you to have any extreme emergency powers but will wait until all parties have been served and given a chance to appear before the court.
If you are successful in obtaining a conservatorship over your father, you would then have limited powers to handle his financial affairs and possibly make medical decisions on his behalf. All of your actions would be regularly reviewed by the court to make certain that you are not misusing your position. Once you have the conservatorship, you could request the court's approval to draft a will and/or trust depending on what assets your father has. If he owns a home in California, you are much better off drafting a trust over a will.
If you do obtain the conservatorship before your father passes away, then you will have to probate your father's estate (if he owned real property or his other assets with no beneficiaries total over $100,000). While some people attempt to do probate themselves, it is a complex process that is driven and controlled by the Probate Code. Due to the multiple forms and legal requirements, most people find it easier to hire an experienced probate attorney to handle the estate. The attorney's fees along with the executor/administrator are driven by the Probate Code.
This information is not intended to substitute for professional legal advice and does not create an attorney-client relationship. You should accept legal advice only from a licensed legal professional with whom you have an attorney-client relationship.