Hello, Lisa:
This sounds familiar to some issues we faced with my 85 y/o grandmother this year. The visions and such may seem odd, but we found that after an evaluation at an Alzheimer's unit, that my grandmother was suffering from delusions. Not Alzheimer's, but another type of delusion that showed up from time to time. Otherwise, my grandmother was really quite healthy, alert and lucid.
We were told that delusions can have many causes, some psychological, some physical, some medical...medications can play a role but also can loneliness, depression and the simple issues that arise when our brains age.
The other issue that arose for us is that we were trying to treat her based on each individual symptom that arose instead of looking at the whole picture. In other words, we were chasing each issue as it reared its head when in fact we needed to have someone evaluate her in a comprehensive way so that all of the issues could be managed. It also helped us to anticipate things instead of being surprised and perplexed when a new symptom arose.
I would consider having your father have a comprehensive work-up by someone specializing in geriatric medicine. We went to Duke University in Durham, NC, but I am sure that there are other similar centers around the country. Ask your primary care physician. A place that treats the whole person i.e. physically, socially, mentally worked best for my grandmother.
Doing this sooner than later is best as what we found was that not treated, her symptoms got worse and she actually started sleep walking and felt unsafe. There was to some degree a sense of denial in the family about her condition and we have moved her into a higher level of care aftger everyone finally realized that she was at risk. She actually had the presence of mind to ask to be moved to a great assisted living facility to help us monitor her and keep her safe.
I did want to say that I sympathize with you as it can be difficult when our parents/grandparents start going through some of these issues. I would encourage you to seek help and support which includes reading up on the issues that the doctors identify as impacting your father.
I wish you the best and trust that my feedback helps ! 
Sincerely,
Melanie