I read the original post and felt sick – for you and your dad, but also because it brings up bad memories.
Don’t know if your dad has Lyme, but know that even if tested – less than half of the people with it don’t test positive the first time, or even sometimes with subsequent testing. The CDC testing is terribly antiquated.
I went on the wild goose chase of seeing 25+ doctors/specialists to try to get answers when not just one, but two of my family members got sick with similar symptoms as your dad. MRI’s, blood work, CT scans, lumbar punctures, etc, etc, etc. Both tested negative for Lyme 3-4 times over 6 months before they finally got a positive test result. By then, the disease went systemic, doxycycline no longer works, and it’s been a living hell of multiple symptoms that’ll ruin your life ever since.
My 25 year old son got it one year, my wife the next (Interestingly they have the same blood type). My son had found a tick after walking in the woods, my wife never saw one. I’ll spare you their separate journeys but is very extensive. But I will add that my wife fainted while doing 50 mph while going on an entrance ramp onto Hwy 100 and is lucky someone was in the car to take the wheel before she smashed into the cement median.
Let’s hope your dad has something else that is better treatable. First thing I recommend is to get on Ivermectin. Doesn’t work for everyone, but many it does. In our case, yes for my wife, no for my son. But it’s cheap and no side effects. Second, see Dr. Kyle Warren in Edina who specializes in these types of infectious disease things. Mainstream doctors that don’t have a positive test result in front of them for Lyme will invariably diagnose it as “in your head” and take anti-depressants. It’s obviously not and it’s called gaslighting. Dr. Warren can help develop a treatment plan.
I hope this narrows down 5 years of learning the hard way into one post.
Good luck, hope your dad turns the corner soon