Anyone have experience with a dementia patient (86) that flips furniture and clears counters tables, closets, etc?

Gerry there is no normal with this destructive disease. All the right things seem to be being done for your Dad. If he is not already in a locked facility that is where he needs to be for his own protection and that of others. In view of these changes it sounds as though his medications may need to be reviewed. Unfortunately a person's previous personality and behavior does not seem to follow them into dementia. It is so sad to see. There is no normal and future behavior is totally unpredictable. This is so hard for you but many people here are ready to offer their support.

Has the doctor who is prescient these drugs been informed of his behavior? Is this a sudden change in his behavior, which might signal an infection?

I'm not sure if you realized it, but your original question received several answers a couple of days ago. Here is a link for your original post. It's almost identical. Maybe you will get some advice there.
https://www.agingcare.com/questions/dementia-patients-flip-furniture-and-toss-rooms-183777.htm

Very astute...in March he went to ER for a fall (after tossing his room), diagnosed with pneumonia and the staff psychiatrist indicated that may have caused his behavior. infection cleared, returned to a facility, within two weeks he continued his destructive behavior. has been to ER a few times since, they always complete urinalysis/blood work to check for infection.

SUNDOWNER'S, posted on your previous question.