Move him close to you; make it easier on yourself. This is a "long haul" situation, and you really can't count on others to visit on a truly regular basis.

My first impression is that he is already past the point when he can live independently! You didn't mention driving, doctor visits, any social outlet, other family, etc.
May be time for family intervention, and figure out next steps. Do you have POA, LIVING WILL, MEDICAL SURROGATE DOCUMENTS??? Lots of important stuff to get a handle on!

I think an unannounced visit is absolutely okay, especially in this case. You can see how he's REALLY living, when he can't "clean up" first, and hopefully you'll be able to remove dangerous items. Have you considered what your options are, when he really cannot be left alone any more? Having thought through different scenarios, and having looked at various options ahead of time, can be very helpful later on. It reduces stress, and you'll be glad you did that.

Marcia, Once you have cameras in the house you’ll have a better understanding of how he is doing on a daily basis. Then you can make decisions appropriate to his needs. Right now you don’t have a clear picture of what is happening so you naturally are worried. You’ll still worry but at least feel like you know what is happening and can intervene when necessary.

I hope you can enjoy some time with your dad during this visit.

My dad wasn't angry. He's lawn mower was delivered today finally. His house looks pretty good. He still has some food in his freezer. Need to get some food and supplies for him. My dad seems fine. Lynn, my dad is like that too. He forgets when I will be in town too. Somehow his days got marked off as done and that I was coming up now. Normally, he has a doctor appointment next week around his birthday. I try to schedule around his birthday and holidays if possible.
Anna, my dad is stubborn and wants to stay at his house. I'm trying to let him stay here as long as possible. We have a meeting with a in home care agency tomorrow. I stopped by a day care today. I'm not sure if my dad would even like that place. I got there later than I wanted too. They don't have transportation to his house. People tell me I need to get him in assisted living. I don't know that my dad would want to stay in one of those. He likes to stay busy doing things. If I put him in an assisted living near his house, will people visit him from his intermediate family or not? If not, I should just move him to my house even through he doesn't want too.
My dad also has problems with his phones. Having video cameras, I would hopefully be able to communicate with him and see that he is okay or sleeping, find out who took my dad somewhere. It would give me piece of mind. After I put two trackers on his phone, that helped a lot especially if one wasn't working. You still wonder who took him where.
I'll check into Simplisafe.

Thank you all!🙂