My dad was recently diagnosed with LBD, but looking back, I think the onset was most likely 5 years ago. Any insight?

Yes, as what Alva referenced about her brother, my stepFIL had the same. Much peace to you.

Thank you so much. I have been reading a lot about the spikes and declines of LBD. My dad also has many other serious medical conditions. I just want him comfortable and safe. Again, thank you for your insight.

It is common of Lewy's. You are correct. You can find out an awful lot by going online and googling Lewy's. There are also support groups if you look up Lewy's Body Dementia Forum. There are also sites on Facebook; one is even done by a man who has Lewy's and lectures around the country (less now I do believe; I haven't been on site for about a year now). My brother was diagnosed a year before his demise from another cause. There are certain hallucinations with Lewy's some visual, the way you "see" the world, and some quite elaborate, as my bro could tell me about whole "pool parties" he saw outside his door in the nighttime, and describe how people were dressed. He knew of his diagnosis of "early Lewy's". There are signs. Loss of sense of smell, imbalance of body, these peculiar hallucinations, a sort of almost seizure like thing where foot taps, difficult to swallow for some moments, and so on. He had them all. He died of another cause before it progressed, could explain his symptoms, and some days were good and some bad. There is a graft out there I saw with how Lewy's differs from other dementias. In Alzheimers the course is slowly all down, in frontal it is stairstep levels down and with Lewy's it is UP AND DOWN, and it is unique in that. Some days good and some bad.
I wish you good luck. My brother said he was glad he knew of his diagnosis and while he couldn't be happy about it he could more understand what was happening to him.