Father refuses care. Any advice?

More details might help. Please fill our your profile, or give us details, so we might answer your questions. And welcome to the Forum.
As is, not much advice but to let your Dad make his own decisions for his own life. If he is competent to do so. And if he is not competent, seeking guardianship so that you can make decisions for your Dad may prove to be very costly, and in the end you may lose a case for guardianship if you Father is at all capable of functioning.

Let him be. If and when he hurts himself or has a crisis, he will be taken to the ER and admitted to the hospital. He'll then be sent to rehab where they won't release him to live alone if he's unable to do so. That's when he's forced to either get help or be moved into managed care permanently.

Or, if he's not rehab worthy, get the social worker at the hospital involved for home care solutions if they want to release him back home to live alone.

If he's of sound mind, he gets to make lots of bad decisions, unfortunately, and you get to clean up the messes. If he's incompetent due to dementia, that's a horse of another color.

Without any details or profile, we can't give you much advice.

What kind of care does he need? What medical conditions is he dealing with? Is he of sound mind? Sorry to answer with questions but it’ll help in answering