Is the Filter Theory committing the ad hoc fallacy and is it unfalsifiable?

 But terminal lucidity, considering alzheimer's damage to the brain, is rather compelling, at least in my opinion.

Do you have any evidence that terminal lucidity happens in patients more than would be expected by chance? People sometimes have good days and sometimes have bad days. If their last day is good, other people remember it. If their last day was bad, people expect it, and don't think about it.

If a person's last day is good in terms of motor skills, would you say that is a sign that people will move their physical arms and legs long after death? If not, why is a good day mentally considered a sign of soul survival?