Elderly cowboy out of control. Any advice?

Take dad out to lunch and remove the weapons. If you cannot get to all of them, for example if they are in a safe, proceed to get guardianship - he is a menace to himself and society.
Do alert Law enforcement. but after you have removed the guns or have confirmed you are unable to do so. Once he realizes you or the sheriff want him to give up the weapons he can become more combative and dangerous.

You have no time to waste, this is a dangerous situation.

Wait a minute. Your father has dementia (after a stroke), he has actively threatened to shot people, he has in fact shot at someone, and you are wondering what to do?

GET THE GUNS AWAY FROM HIM!!

Good grief. You think you feel bad about upsetting Cowboy Dad -- how would you feel about attending the funeral service for your nephew? Or a social worker? Or a paramedic?

Use littletonway's suggestion of removing him from the house and having someone remove the guns, and the sherriff there to explain it when you get home.

Use Pam's suggestion about notifying law enforcement.

A person with dementia is not safe with guns. No way, no how.

I think you may be too close to the situation, and have just accepted what you call your Dad's cowboy ways all your life. Try to read your post as if someone else had written it. What would you tell that poster?

Take him out to lunch and have some remove all the weapons/bullets immediately. A rougher approach would be have the sheriff come talk to Father, explain what a danger he presents to the community and why he is removing all the weapons. Sheriff could bring a letter from Father's doctor. The life you save could be someone you love!

You should at least notify the County Sheriff and 911 services. Save a Life.

Stardust14, I read your profile. Even with one of those Life Alert pendants, first responders may not go onto your Dad's property if they feel it isn't secure [meaning there could be a threat to their life]. Your Dad could start shooting at them.

I realize your Dad probably feels it's his 2nd Amendment right to own firearms, but with his unsteady health, this is a tricky situation. Would it be possible to take away all the bullets, but let him keeps his firearms? Or would he drive into town to buy ammo, even though it sounds like he shouldn't be driving at this point in time.

move him to the southern border and get him bigger firepower .