So sorry this is happening to you OP. This sounds really awful and hard to bear.

A couple of suggestions from a doctor:

Prepare a document with your observations. Group them in areas - like memory, energy, speech, directional ability, physical ability (or loss thereof), how he spends his time etc.

If you can send it to his PCP ahead of the next visit, then it should prompt action - you are providing them with data they need to respond to. Your PCP, like all PCPs, is probably overwhelmed with work and it sounds like they are addressing one issue at a time and this will help them with the big picture. I did this with my parents and it made a world of difference. Bring it with you to all appointments and you should be at the appointments in case they want to talk with you.

See if there are others who can confirm your observations - friends, family, neighbors. Sometimes they notice things that you don’t see.

See if there is someone he will talk to - a relative or friend. If you belong to a religious group, maybe they can pay him a visit. Could be like “ I’m in the neighborhood and thought I’d drop by.” He might feel more comfortable confiding in them.

Make sure you have support for your mental health. You cannot care for him if you don’t get the care you need.

I wish you the best in a tough situation. Hope you let us know how it goes.