Don’t know where to start?

You can't save a person from himself............and that's the truth.
Wishing you the best of luck moving forward

PMemory, I think you're facing an uphill battle on a slick mountain.    I agree with AlvaDeer; this is a situation beyond your control.   Unfortunately it sounds as if your father needs to be in a care facility, what used to be known as the psychiatric hospitals.     His needs and mental issues are well beyond what any single person can control, or even address and possibly heal.

Try to shift your focus to the better days, and remember that not necessarily through fault of his own, his mental state has changed him from how he was/might have been years before these ravages of mind and body took control.

Also sending hugs to you... I don't know how you care for someone who doesn't want that care for themselves, but you need to make sure you are taking care of you as this amount of emotional and mental stress will affect you. Wishing you peace in your heart that you cannot/should not control everything (even worthy things) and that you are not ultimately responsible for his life. But, bless you for your yeoman's effort.

This is so sad. Just want to send you a giant hug and wish you and your family well.

You can of course apply for Guardianship. The real question is do you really want it and how could you inforce it. I think there is very little that you can do in all honestly unless you want to go the entire route of guardianship and having him put in someplace where he can be contained on a mental hold. The question is whether you choose to do that, or let nature take its course. For myself I think I would do the latter at this point. Your Dad is on a mission that is truly suicidal, and there is little that will save him either way, and blame and guilt will be leveled at you at this point no matter WHAT you do. I would leave this in the hands of social services and I would tell them that you would like a state appointed guardianship. You will have no say at that point. THat is fine. Visit him when and where you are able, give what love you are able, and let things follow the course that it seems to me is inevitable. I am so very sorry. Not everything can be fixed.